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putnam_2014_a1
Require Import Reals Factorial Znumtheory Coquelicot.Derive. Theorem putnam_2014_a1 (f : R -> R := fun x => (1 - x + x^2) * (exp x)) (hf : forall x : R, forall n : nat, ex_derive_n f n x) (coeff : nat -> R := fun i => Derive_n f i 0 / INR (fact i)) (n : nat) (hcoeff : coeff n <> 0) : exists a b:...
import Mathlib open Topology Filter /-- Prove that every nonzero coefficient of the Taylor series of \[(1 - x + x^2)e^x\] about $x=0$ is a rational number whose numerator (in lowest terms) is either $1$ or a prime number. -/ theorem putnam_2014_a1 (f : ℝ β†’ ℝ) (hf : βˆ€ x : ℝ, f x = (1 - x + x ^ 2) * Real.exp x) (hfdiff...
putnam_1962_a6
Require Import Ensembles QArith. Theorem putnam_1962_a6 (A : Ensemble Q) (hSSadd : forall a b : Q, (A a /\ A b) -> A (a + b)) (hSSprod : forall a b : Q, (A a /\ A b) -> A (a * b)) (hSScond : forall r : Q, (A r \/ A (-r) \/ r = 0) /\ ~(A r \/ A (-r)) /\ ~(A r /\ r = 0) /\ ~(A (-r) /\ r = 0)) : A = (f...
import Mathlib /-- Let $S$ be a set of rational numbers such that whenever $a$ and $b$ are members of $S$, so are $a+b$ and $ab$, and having the property that for every rational number $r$ exactly one of the following three statements is true: \[ r \in S, -r \in S, r = 0. \] Prove that $S$ is the set of all positive r...
putnam_1962_b6
Require Import Reals Ensembles Coquelicot.Hierarchy Finite_sets. Local Coercion INR : nat >-> R. Theorem putnam_1962_b6 (n : nat) (a b : nat -> R) (xs : Ensemble R) (f : R -> R := (fun x : R => sum_n (fun k : nat => a k * sin (k * x) + b k * cos (k * x)) n)) (hf1 : forall x : R, (0 <= x /\ x <= 2 ...
import Mathlib open Real /-- Let \[ f(x) = \sum_{k=0}^n a_k \sin kx + b_k \cos kx, \] where $a_k$ and $b_k$ are constants. Show that, if $\lvert f(x) \rvert \le 1$ for $0 \le x \le 2 \pi$ and $\lvert f(x_i) \rvert = 1$ for $0 \le x_1 < x_2 < \cdots < x_{2n} < 2 \pi$, then $f(x) = \cos (nx + a)$ for some constant $a$....
putnam_1966_a4
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals sequences. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Variable R : realType. Theorem putnam_1966_a4 (a : nat -> int) (ha1 : a 1%nat = 2) (hai : fo...
import Mathlib open Topology Filter /-- Prove that the $n$th item in the ascending list of non-perfect-square positive integers equals $n + \{\sqrt{n}\}$, where $\{m\}$ denotes the closest integer to $m$. -/ theorem putnam_1966_a4 (a : β„• β†’ β„€) (ha1 : a 1 = 2) (hai : βˆ€ n β‰₯ 1, a (n + 1) = (if βˆƒ m : β„€, m^2 = a n + 1 = Tr...
putnam_2005_b2
Require Import Nat List Reals Coquelicot.Coquelicot. Import ListNotations. Definition putnam_2005_b2_solution (n: nat) (k: list nat) := (n, k) = (1%nat, [1%nat]) \/ (n, k) = (3%nat, [2%nat; 3%nat; 6%nat]) \/ (n, k) = (3%nat, [2%nat; 6%nat; 3%nat]) \/ (n, k) = (3%nat, [3%nat; 2%nat; 6%nat]) \/ (n, k) = (3%nat, [3%nat; 6...
import Mathlib open Nat Set -- Note: uses β„• β†’ β„• instead of Fin n β†’ β„• abbrev putnam_2005_b2_solution : Set (β„• Γ— (β„• β†’ β„€)) := sorry -- {(n, k) : β„• Γ— (β„• β†’ β„€) | (n = 1 ∧ k 0 = 1) ∨ (n = 3 ∧ (k '' {0, 1, 2} = {2, 3, 6})) ∨ (n = 4 ∧ (βˆ€ i : Fin 4, k i = 4))} /-- Find all positive integers $n,k_1,\dots,k_n$ such that $k_1+\cd...
putnam_1970_b5
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals exp sequences topology normedtype. From mathcomp Require Import classical_sets. Import numFieldNormedType.Exports. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. L...
import Mathlib open Metric Set EuclideanGeometry Filter Topology /-- Let $u_n$ denote the function $u_n(x) = -n$ if $x \leq -n$, $x$ if $-n < x \leq n$, and $n$ otherwise. Let $F$ be a function on the reals. Show that $F$ is continuous if and only if $u_n \circ F$ is continuous for all natural numbers $n$. -/ theorem...
putnam_1972_b6
Require Import Nat Reals. From Coquelicot Require Import Complex Hierarchy. (* uses (nat -> nat) instead of ('I_k -> nat) *) Theorem putnam_1972_b6 (k : nat) (n : nat -> nat) (zpoly : C -> C := fun z : C => (1 + sum_n (fun i => Cpow z (n i)) (k - 1))%C) (hk : (k >= 1)%nat) (hn : (forall i : nat, i <...
import Mathlib open EuclideanGeometry Filter Topology Set MeasureTheory Metric /-- Let $n_1 < n_2 < \dots < n_k$ be a set of positive integers. Prove that the polynomail $1 + z^{n_1} + z^{n_2} + \dots + z^{n_k}$ has not roots inside the circle $|z| < (\frac{\sqrt{5}-1}{2}$. -/ theorem putnam_1972_b6 (k : β„•) (hk : k β‰₯...
putnam_2003_b4
Require Import Reals ZArith Coquelicot.Coquelicot. Theorem putnam_2003_b4 (a b c d e: Z) (r1 r2 r3 r4: R) (ha : ~ Z.eq a 0) : let a := IZR a in let b := IZR b in let c := IZR c in let d := IZR d in let e := IZR e in (forall (z: R), a * z ^ 4 + b * z ^ 3 + c * z ^ 2 + d * z + e =...
import Mathlib open MvPolynomial Set Nat /-- Let $f(z)=az^4+bz^3+cz^2+dz+e=a(z-r_1)(z-r_2)(z-r_3)(z-r_4)$ where $a,b,c,d,e$ are integers, $a \neq 0$. Show that if $r_1+r_2$ is a rational number and $r_1+r_2 \neq r_3+r_4$, then $r_1r_2$ is a rational number. -/ theorem putnam_2003_b4 (f : ℝ β†’ ℝ) (a b c d e : β„€) ...
putnam_2005_a5
Require Import Reals Coquelicot.Coquelicot. Definition putnam_2005_a5_solution := PI * ln 2 / 8. Theorem putnam_2005_a5 : RInt (fun x => ln (x + 1) / (x ^ 2 + 1)) 0 1 = putnam_2005_a5_solution. Proof. Admitted.
import Mathlib open Nat Set noncomputable abbrev putnam_2005_a5_solution : ℝ := sorry -- Real.pi * (Real.log 2) / 8 /-- Evaluate $\int_0^1 \frac{\ln(x+1)}{x^2+1}\,dx$. -/ theorem putnam_2005_a5 : ∫ x in (0:ℝ)..1, (Real.log (x+1))/(x^2 + 1) = putnam_2005_a5_solution := sorry
putnam_2008_b4
Require Import Nat ZArith Reals Coquelicot.Coquelicot. Theorem putnam_2008_b4 (p: nat) (hp : Znumtheory.prime (Z.of_nat p)) (c: nat -> Z) (n: nat) (h : nat -> Z := fun x => floor (sum_n (fun i => IZR (c i) * INR (x ^ i)) n)) (hh : forall (i j: nat), i <> j /\ and (le 0 i) (le i (p ^ 2 - 1)) /\ a...
import Mathlib open Filter Topology Set Nat /-- Let $p$ be a prime number. Let $h(x)$ be a polynomial with integer coefficients such that $h(0), h(1), \dots, h(p^2-1)$ are distinct modulo $p^2$. Show that $h(0), h(1), \dots, h(p^3-1)$ are distinct modulo $p^3$. -/ theorem putnam_2008_b4 (p : β„•) (hp : Nat.Prime p) (h ...
putnam_1976_b6
From mathcomp Require Import all_algebra all_ssreflect. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope nat_scope. Theorem putnam_1976_b6 (sigma : nat -> int := fun N => \sum_(d <- divisors N) d) : forall N : nat, sigma N = (N.*2 + 1) -> (exists m : nat, odd m = tru...
import Mathlib open Polynomial Filter Topology ProbabilityTheory MeasureTheory /-- Let $\sigma(N)$ denote the sum of all positive integer divisors of $N$, including $1$ and $N$. Call a positive integer $N$ \textit{quasiperfect} if $\sigma(N) = 2N + 1$. Prove that every quasiperfect number is the square of an odd inte...
putnam_2007_b3
Require Import Reals Coquelicot.Coquelicot. Definition putnam_2007_b3_solution := let a := (1 + sqrt 5) / 2 in (2 ^ 2006 / sqrt 5) * (a ^ 3997 - Rpower a (-3997)). Theorem putnam_2007_b3 (X := fix x (n: nat) := match n with | O => 1 | S n' => 3 * x n' + IZR (floor (x n' * sqrt 5)) end) ...
import Mathlib open Set Nat Function noncomputable abbrev putnam_2007_b3_solution : ℝ := sorry -- (2 ^ 2006 / Real.sqrt 5) * (((1 + Real.sqrt 5) / 2) ^ 3997 - ((1 + Real.sqrt 5) / 2) ^ (-3997 : β„€)) /-- Let $x_0 = 1$ and for $n \geq 0$, let $x_{n+1} = 3x_n + \lfloor x_n \sqrt{5} \rfloor$. In particular, $x_1 = 5$, $x_...
putnam_2004_a3
Require Import Reals Coquelicot.Coquelicot. Theorem putnam_2004_a3 (u : nat -> R) (hubase : u O = 1 /\ u (S O) = 1 /\ u (S (S O)) = 1) (hudet : forall n : nat, u n * u (Nat.add n 3) - u (Nat.add n 1) * u (Nat.add n 2) = INR (fact n)) : forall n : nat, exists m : Z, u n = IZR m. Proof. Admitted.
import Mathlib open Nat Topology Filter /-- Define a sequence $\{u_n\}_{n=0}^\infty$ by $u_0=u_1=u_2=1$, and thereafter by the condition that $\det \begin{pmatrix} u_n & u_{n+1} \\ u_{n+2} & u_{n+3} \end{pmatrix} = n!$ for all $n \geq 0$. Show that $u_n$ is an integer for all $n$. (By convention, $0!=1$.) -/ theorem ...
putnam_1990_b3
Require Import Ensembles Finite_sets Reals Coquelicot.Coquelicot. Open Scope R. Theorem putnam_1990_b3 (E : Ensemble (matrix 2 2)) (hE : forall (A: matrix 2 2), E A -> forall (i j: nat), and (le 0 i) (lt i 2) /\ and (le 0 j) (lt j 2) -> (coeff_mat 0 A i j) <= 200 /\ exists (m: nat), coeff_mat ...
import Mathlib open Filter Topology Nat /-- Let $S$ be a set of $2 \times 2$ integer matrices whose entries $a_{ij}$ (1) are all squares of integers, and, (2) satisfy $a_{ij} \leq 200$. Show that if $S$ has more than $50387$ ($=15^4-15^2-15+2$) elements, then it has two elements that commute. -/ theorem putnam_1990_b...
putnam_1992_a4
Require Import Nat Reals Coquelicot.Coquelicot. Open Scope R. Definition putnam_1992_a4_solution (k : nat) := if odd k then 0 else pow (-1) (k/2) * INR (fact k). Theorem putnam_1992_a4 (f : R -> R) (hfdiff : forall k : nat, continuity (Derive_n f k) /\ forall x : R, ex_derive (Derive_n f k) x) (hf : forall ...
import Mathlib open Topology Filter Nat Function abbrev putnam_1992_a4_solution : β„• β†’ ℝ := sorry -- fun k ↦ ite (Even k) ((-1) ^ (k / 2) * factorial k) 0 /-- Let $f$ be an infinitely differentiable real-valued function defined on the real numbers. If \[ f\left( \frac{1}{n} \right) = \frac{n^2}{n^2 + 1}, \qquad n = 1,...
putnam_1990_b2
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals exp sequences normedtype topology. From mathcomp Require Import classical_sets. Import numFieldNormedType.Exports. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. L...
import Mathlib open Filter Topology Nat /-- Prove that for $|x|<1$, $|z|>1$, $1+\sum_{j=1}^\infty (1+x^j)P_j=0$, where $P_j$ is $\frac{(1-z)(1-zx)(1-zx^2) \cdots (1-zx^{j-1})}{(z-x)(z-x^2)(z-x^3) \cdots (z-x^j)}$. -/ theorem putnam_1990_b2 (x z : ℝ) (P : β„• β†’ ℝ) (xlt1 : |x| < 1) (zgt1 : |z| > 1) (hP : βˆ€ j β‰₯ 1, P j = (...
putnam_2018_b6
Require Import Nat List Ensembles Finite_sets Reals. Theorem putnam_2018_b6 (E: Ensemble (list nat) := fun l => length l = 2018 /\ forall (n: nat), (List.In n l) -> (n = 1 \/ n = 2 \/ n = 3 \/ n = 4 \/ n = 5 \/ n = 6 \/ n = 10) /\ fold_left Nat.add l 0 = 3860 ) (n : nat) : cardinal (lis...
import Mathlib /-- Let $S$ be the set of sequences of length $2018$ whose terms are in the set $\{1,2,3,4,5,6,10\}$ and sum to $3860$. Prove that the cardinality of $S$ is at most $2^{3860} \cdot \left(\frac{2018}{2048}\right)^{2018}$. -/ theorem putnam_2018_b6 (S : Finset (Fin 2018 β†’ β„€)) (hS : S = {s : Fin 2018 β†’...
putnam_2009_a2
Require Import Reals Coquelicot.Coquelicot. Definition putnam_2009_a2_solution : (R -> R) := fun x => Rpower 2 (-1 / 12) * Rpower (sin (6 * x + PI / 4) / (cos (6 * x + PI / 4)) ^ 2) (1 / 6). Theorem putnam_2009_a2 (f g h: R -> R) (a b: R) (hab : a < 0 < b) (hdiff : forall (x: R), a < x < b -> ex_derive...
import Mathlib open Topology MvPolynomial Filter Set noncomputable abbrev putnam_2009_a2_solution : ℝ β†’ ℝ := sorry -- fun x ↦ 2 ^ (-(1 : ℝ) / 12) * (Real.sin (6 * x + Real.pi / 4) / (Real.cos (6 * x + Real.pi / 4)) ^ 2) ^ ((1 : ℝ) / 6) /-- Functions $f,g,h$ are differentiable on some open interval around $0$ and sati...
putnam_2008_b5
Require Import Reals QArith Coquelicot.Coquelicot. From mathcomp Require Import div. Open Scope R. Definition putnam_2008_b5_solution (f : R -> R) := exists n : Z, f = (fun x => x + IZR n) \/ f = (fun x => -x + IZR n). Theorem putnam_2008_b5 (f: R -> R) (hf : (forall x: R, ex_derive f x) /\ continuity (Derive f...
import Mathlib open Filter Topology Set Nat abbrev putnam_2008_b5_solution : Set (ℝ β†’ ℝ) := sorry -- {fun (x : ℝ) => x + n | n : β„€} βˆͺ {fun (x : ℝ) => -x + n | n : β„€} /-- Find all continuously differentiable functions f : \mathbb{R} \to \mathbb{R} such that for every rational number $q$, the number $f(q)$ is rational ...
putnam_2010_a2
Require Import Reals Coquelicot.Coquelicot. Definition putnam_2010_a2_solution (f: R -> R) := exists (c d: R), f = (fun x => c * x + d). Theorem putnam_2010_a2 (f: R -> R) : (forall (x: R) (n: nat), gt n 0 -> ex_derive f x /\ Derive f x = (f (x + (INR n)) - f x) / (INR n)) <-> putnam_2010_a2_solution f. Proof. ...
import Mathlib abbrev putnam_2010_a2_solution : Set (ℝ β†’ ℝ) := sorry -- {f : ℝ β†’ ℝ | βˆƒ c d : ℝ, βˆ€ x : ℝ, f x = c*x + d} /-- Find all differentiable functions $f:\mathbb{R} \to \mathbb{R}$ such that \[ f'(x) = \frac{f(x+n)-f(x)}{n} \] for all real numbers $x$ and all positive integers $n$. -/ theorem putnam_2010_a2 : {...
putnam_1992_a2
Require Import Reals Binomial Factorial Coquelicot.Coquelicot. Open Scope R. Definition putnam_1992_a2_solution := 1992. Theorem putnam_1992_a2 (C : R -> R := fun a => (Derive_n (fun x => Rpower (1 + x) a) 1992) 0 / INR (fact 1992)) : RInt (fun y => C (-y - 1) * sum_n_m (fun k => 1 / (y + INR k)) 1 1992) 0 1 = ...
import Mathlib open Topology Filter abbrev putnam_1992_a2_solution : ℝ := sorry -- 1992 /-- Define $C(\alpha)$ to be the coefficient of $x^{1992}$ in the power series about $x=0$ of $(1 + x)^\alpha$. Evaluate \[ \int_0^1 \left( C(-y-1) \sum_{k=1}^{1992} \frac{1}{y+k} \right)\,dy. \] -/ theorem putnam_1992_a2 (C : ℝ β†’...
putnam_1969_b3
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals exp sequences topology normedtype trigo. From mathcomp Require Import classical_sets. Import numFieldNormedType.Exports. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_sc...
import Mathlib open Matrix Filter Topology Set Nat /-- Suppose $T$ is a sequence which satisfies $T_n * T_{n+1} = n$ whenever $n \geq 1$, and also $\lim_{n \to \infty} \frac{T_n}{T_{n+1}} = 1. Show that $\pi * T_1^2 = 2$. -/ theorem putnam_1969_b3 (T : β„• β†’ ℝ) (hT1 : βˆ€ n : β„•, n β‰₯ 1 β†’ (T n) * (T (n + 1)) = n) (hT2 : Te...
putnam_2022_a1
Require Import Reals Coquelicot.Coquelicot. Definition putnam_2022_a1_solution : R -> R -> Prop := fun a b => (a = 0 /\ b = 0) \/ (Rabs a >= 1) \/ (0 < Rabs a < 1 /\ (b < ln (1 + ((1 - sqrt (1 - a ^2))/ a) ^ 2) - a * (1 - sqrt (1 - a ^ 2) / a) \/ b > ln (1 + ((1 + sqrt (1 - a ^ 2)) / a) ^ 2) - a * (1 + sqrt (1 - a ^ 2)...
import Mathlib open Polynomial abbrev putnam_2022_a1_solution : Set (ℝ Γ— ℝ) := sorry -- {(a, b) | (a = 0 ∧ b = 0) ∨ 1 ≀ |a| ∨ (0 < |a| ∧ |a| < 1 ∧ letI rm := (1 - √(1 - a ^ 2)) / a; letI rp := (1 + √(1 - a ^ 2)) / a; (b < Real.log (1 + rm ^ 2) - a * rm ∨ b > Real.log (1 + rp ^ 2) - a * rp))} /-- Determine all ordered...
putnam_1985_a1
Require Import Ensembles Finite_sets Nat. Definition putnam_1985_a1_solution := (10, 10, 0, 0). Theorem putnam_1985_a1 : let (abc, d) := putnam_1985_a1_solution in let (ab, c) := abc in let (a, b) := ab in cardinal ((Ensemble nat) * (Ensemble nat) * (Ensemble nat)) (fun A => let (A1A2, A3) := A in let (A1, A2)...
import Mathlib open Set abbrev putnam_1985_a1_solution : β„• Γ— β„• Γ— β„• Γ— β„• := sorry -- (10, 10, 0, 0) /-- Determine, with proof, the number of ordered triples $(A_1, A_2, A_3)$ of sets which have the property that \begin{enumerate} \item[(i)] $A_1 \cup A_2 \cup A_3 = \{1,2,3,4,5,6,7,8,9,10\}$, and \item[(ii)] $A_1 \cap A...
putnam_2022_a6
Require Import Nat Reals Coquelicot.Hierarchy. From mathcomp Require Import div fintype seq ssralg ssrbool ssrnat ssrnum . Definition putnam_2022_a6_solution := fun n : nat => n. Theorem putnam_2022_a6 (N : nat) (M : nat) (n := mul N 2) (i0 : 'I_n) (sumIntervals : ('I_n -> R) -> nat -> R := fun s k ...
import Mathlib open Set -- Note: uses (β„• β†’ ℝ) instead of (Fin (2 * n) β†’ ℝ) abbrev putnam_2022_a6_solution : β„• β†’ β„• := sorry -- (fun n : β„• => n) /-- Let $n$ be a positive integer. Determine, in terms of $n$, the largest integer $m$ with the following property: There exist real numbers $x_1,\dots,x_{2n}$ with $-1<x_1<x_...
putnam_1986_a6
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Variable R : realType. Definition putnam_1986_a6_solution : (nat -> nat) -> nat -> R := fun b n => (\prod_(1 <= i ...
import Mathlib open Real Equiv noncomputable abbrev putnam_1986_a6_solution : (β„• β†’ β„•) β†’ β„• β†’ ℝ := sorry -- fun b n ↦ (∏ i : Finset.Icc 1 n, b i) / Nat.factorial n /-- Let $a_1, a_2, \dots, a_n$ be real numbers, and let $b_1, b_2, \dots, b_n$ be distinct positive integers. Suppose that there is a polynomial $f(x)$ sat...
putnam_2004_b1
Require Import Nat Reals QArith Coquelicot.Coquelicot. Theorem putnam_2004_b1 (c : nat -> Z) (n : nat) (r : Q) (Preq0 : sum_n (fun i => IZR (c i) * (Q2R r) ^ i) n = 0) : forall i : nat, lt i n -> exists m : Z, IZR m = sum_n (fun j => IZR (c (sub n j)) * (Q2R r) ^ (i + 1 - j)) i. Proof. Admitted.
import Mathlib open Nat Topology Filter /-- Let $P(x)=c_nx^n+c_{n-1}x^{n-1}+\cdots+c_0$ be a polynomial with integer coefficients. Suppose that $r$ is a rational number such that $P(r)=0$. Show that the $n$ numbers $c_nr,\,c_nr^2+c_{n-1}r,\,c_nr^3+c_{n-1}r^2+c_{n-2}r,\dots,\,c_nr^n+c_{n-1}r^{n-1}+\cdots+c_1r$ are int...
putnam_2013_b2
Require Import Ensembles Finite_sets Reals Coquelicot.Coquelicot. Definition putnam_2013_b2_solution : R := 3. Theorem putnam_2013_b2 (E: Ensemble (R -> R) := fun f => forall (x : R), exists (a : nat -> R) (N : nat), f x = 1 + sum_n_m (fun n => a n * cos (2 * PI * INR n * x)) 1 N /\ f x >= 0 /\ forall (n: nat)...
import Mathlib open Function Set abbrev putnam_2013_b2_solution : ℝ := sorry -- 3 /-- Let $C = \bigcup_{N=1}^\infty C_N$, where $C_N$ denotes the set of those `cosine polynomials' of the form \[ f(x) = 1 + \sum_{n=1}^N a_n \cos(2 \pi n x) \] for which: \begin{enumerate} \item[(i)] $f(x) \geq 0$ for all real $x$, and ...
putnam_2012_a6
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals normedtype topology sequences measure lebesgue_measure lebesgue_integral. From mathcomp Require Import classical_sets. Import numFieldNormedType.Exports. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Def...
import Mathlib open Matrix Function -- Note: this formalization differs from the original problem wording in only allowing axis-aligned rectangles. The problem is solvable given this weaker hypothesis. abbrev putnam_2012_a6_solution : Prop := sorry -- True /-- Let $f(x,y)$ be a continuous, real-valued function on $\m...
putnam_1964_a1
From mathcomp Require Import all_algebra all_ssreflect fintype. From mathcomp Require Import reals. From mathcomp Require Import classical_sets cardinality. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Local Open Scope classical_set_scope. Local Open S...
import Mathlib /-- Let $A_1, A_2, A_3, A_4, A_5, A_6$ be distinct points in the plane. Let $D$ be the longest distance between any pair, and let $d$ the shortest distance. Show that $\frac{D}{d} \geq \sqrt 3$. -/ theorem putnam_1964_a1 (A : Finset (EuclideanSpace ℝ (Fin 2))) (hAcard : A.card = 6) (dists : Set ℝ) (hdis...
putnam_2021_a4
Require Import Reals Coquelicot.Coquelicot. Definition putnam_2021_a4_solution := (sqrt 2 / 2) * PI * ln 2 / ln 10. Theorem putnam_2021_a4 (I : nat -> R := fun r => RInt (fun x => RInt (fun y => (1 + 2 * x ^ 2) / (1 + x ^ 4 + 6 * x ^ 2 * y ^ 2 + y ^ 4) - (1 + y ^ 2) / (2 + x ^ 4 + y ^ 4)) 0 (sqrt (INR r ^ 2 - x ^...
import Mathlib open Filter Topology Metric noncomputable abbrev putnam_2021_a4_solution : ℝ := sorry -- ((Real.sqrt 2) / 2) * Real.pi * Real.log 2 /-- Let \[ I(R) = \iint_{x^2+y^2 \leq R^2} \left( \frac{1+2x^2}{1+x^4+6x^2y^2+y^4} - \frac{1+y^2}{2+x^4+y^4} \right)\,dx\,dy. \] Find \[ \lim_{R \to \infty} I(R), \] or sh...
putnam_1986_b4
Require Import Reals Ranalysis Coquelicot.Coquelicot. Definition putnam_1986_b4_solution := True. Theorem putnam_1986_b4 (G : R -> R) (hGeq : forall (r: R), exists (m n: Z), G r = Rabs (r - sqrt (IZR (m ^ 2 + 2 * n ^ 2)))) (hGlb : forall (r: R), forall (m n: Z), G r <= Rabs (r - sqrt (IZR (m ^ 2 + 2 * n ^ 2...
import Mathlib open Real Equiv Polynomial Filter Topology abbrev putnam_1986_b4_solution : Prop := sorry -- True /-- For a positive real number $r$, let $G(r)$ be the minimum value of $|r - \sqrt{m^2+2n^2}|$ for all integers $m$ and $n$. Prove or disprove the assertion that $\lim_{r\to \infty}G(r)$ exists and equals...
putnam_1971_a6
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals exp sequences topology. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Variable R : realType. Theorem putnam_1971_a6 (c : R) (hc : forall n : int, n > 0 -...
import Mathlib open Set MvPolynomial /-- Let $c$ be a real number such that $n^c$ is an integer for every positive integer $n$. Show that $c$ is a non-negative integer. -/ theorem putnam_1971_a6 (c : ℝ) (hc : βˆ€ n : β„€, n > 0 β†’ βˆƒ m : β„€, (n : ℝ)^c = m) : βˆƒ m : β„€, m β‰₯ 0 ∧ c = m := sorry
putnam_2002_a1
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals normedtype sequences topology derive. From mathcomp Require Import classical_sets. Import numFieldNormedType.Exports. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope...
import Mathlib open Nat abbrev putnam_2002_a1_solution : β„• β†’ β„• β†’ ℝ := sorry -- (fun k n : β„• => (-k) ^ n * (n)!) /-- Let $k$ be a fixed positive integer. The $n$-th derivative of $\frac{1}{x^k-1}$ has the form $\frac{P_n(x)}{(x^k-1)^{n+1}}$ where $P_n(x)$ is a polynomial. Find $P_n(1)$. -/ theorem putnam_2002_a1 (k : ...
putnam_1969_a4
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals exp sequences topology normedtype measure lebesgue_measure lebesgue_integral. From mathcomp Require Import classical_sets. Import numFieldNormedType.Exports. Import Order.TTheory GRing.Theory Num.Theory. Set Implicit Arguments. ...
import Mathlib open Matrix Filter Topology Set Nat /-- Show that $\int_0^1 x^x dx = \sum_{n=1}^{\infty} (-1)^{n+1}n^{-n}$. -/ theorem putnam_1969_a4 : Tendsto (fun n => βˆ‘ i ∈ Finset.Icc (1 : β„€) n, (-1)^(i+1)*(i : ℝ)^(-i)) atTop (𝓝 (∫ x in Ioo (0 : ℝ) 1, x^x)) := sorry
putnam_1964_b2
From mathcomp Require Import all_algebra all_ssreflect fintype. From mathcomp Require Import classical_sets cardinality. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope classical_set_scope. Local Open Scope card_scope. Theorem putnam_1964_b2 (A : finType) (n...
import Mathlib open Set Function Filter Topology /-- Let $S$ be a finite set. A set $P$ of subsets of $S$ has the property that any two members of $P$ have at least one element in common and that $P$ cannot be extended (whilst keeping this property). Prove that $P$ contains exactly half of the subsets of $S$. -/ theo...
putnam_2010_b1
Require Import Reals Coquelicot.Coquelicot. Definition putnam_2010_b1_solution := False. Theorem putnam_2010_b1 : (exists (a: nat -> R), forall (m: nat), gt m 0 -> Series (fun i => (a i) ^ m) = (INR m)) <-> putnam_2010_b1_solution. Proof. Admitted.
import Mathlib open Filter Topology Set abbrev putnam_2010_b1_solution : Prop := sorry -- False /-- Is there an infinite sequence of real numbers $a_1, a_2, a_3, \dots$ such that \[ a_1^m + a_2^m + a_3^m + \cdots = m \] for every positive integer $m$? -/ theorem putnam_2010_b1 : (βˆƒ a : β„• β†’ ℝ, βˆ€ m : β„•, m > 0 β†’ βˆ‘' i : ...
putnam_2009_b5
Require Import Reals Coquelicot.Coquelicot. Theorem putnam_2009_b5 (f: R -> R) (hf : forall (x: R), 1 < x -> (ex_derive f x /\ Derive f x = (x ^ 2 - (f x) ^ 2) / (x ^ 2 * ((f x) ^ 2 + 1)))) : is_lim f p_infty p_infty. Proof. Admitted.
import Mathlib open Topology MvPolynomial Filter Set Metric /-- Let $f: (1, \infty) \to \mathbb{R}$ be a differentiable function such that \[ f'(x) = \frac{x^2 - f(x)^2}{x^2 (f(x)^2 + 1)} \qquad \mbox{for all $x>1$.} \] Prove that $\lim_{x \to \infty} f(x) = \infty$. -/ theorem putnam_2009_b5 (f : ℝ β†’ ℝ) (hfdiff : D...
putnam_1971_a3
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals normedtype. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Variable R : realType. Theorem putnam_1971_a3 (a b c : R * R) (r : R) (habclattice : fst a ...
import Mathlib open Set /-- The three vertices of a triangle of sides $a,b,c$ are lattice points and lie on a circle of radius $R$. Show that $abc \geq 2R$. -/ theorem putnam_1971_a3 (a b c : ℝ Γ— ℝ) (R : ℝ) (habclattice : a.1 = round a.1 ∧ a.2 = round a.2 ∧ b.1 = round b.1 ∧ b.2 = round b.2 ∧ c.1 = round ...
putnam_2009_a1
Require Import Reals GeoCoq.Main.Tarski_dev.Ch16_coordinates_with_functions. Context `{T2D:Tarski_2D} `{TE:@Tarski_euclidean Tn TnEQD}. Open Scope R. Definition putnam_2009_a1_solution := True. Theorem putnam_2009_a1 : (forall f: Tpoint -> R, (forall (A B C D: Tpoint), Square A B C D -> f A + f B + f C + ...
import Mathlib open Topology MvPolynomial Filter abbrev putnam_2009_a1_solution : Prop := sorry -- True /-- Let $f$ be a real-valued function on the plane such that for every square $ABCD$ in the plane, $f(A)+f(B)+f(C)+f(D)=0$. Does it follow that $f(P)=0$ for all points $P$ in the plane? -/ theorem putnam_2009_a1 : ...
putnam_1971_a4
Require Import Nat Reals Coquelicot.Coquelicot. Theorem putnam_1971_a4 (epsilon : R) (hepsilon : 0 < epsilon < 1) (P : nat -> (R * R) -> R := fun n '(x, y) => (x + y)^n * (x^2 - (2 - epsilon)*x*y + y^2)) : exists N : nat, forall n : nat, ge n N -> (exists (k : nat) (coeff : (nat * nat) -> R), (...
import Mathlib open Set MvPolynomial /-- Show that for $\epsilon \in (0,1)$, the expression $(x + y)^n (x^2 - 2-\epsilon)xy + y^2)$ is a polynomial with positive coefficients for $n$ sufficiently large, where $n$ is an integer. -/ theorem putnam_1971_a4 (Ξ΅ : ℝ) (hΞ΅ : 0 < Ξ΅ ∧ Ξ΅ < 1) (P : β„• β†’ ℝ β†’ MvPolynomial (Fin 2) ℝ...
putnam_2010_b4
Require Import Reals Coquelicot.Coquelicot. Definition P : (nat -> R) -> nat -> R -> R := fun c n x => sum_n (fun i => c i * x ^ i) n. Definition putnam_2010_b4_solution (c1 c2: nat -> R) (n m: nat) := exists (a b c d: R), b * c - a * d = 1 /\ P c1 n = (fun x => a * x + b) /\ P c2 m = (fun x => c * x + d). Theorem putn...
import Mathlib open Filter Topology Set abbrev putnam_2010_b4_solution : Set (Polynomial ℝ Γ— Polynomial ℝ) := sorry -- {(p, q) : Polynomial ℝ Γ— Polynomial ℝ | p.degree ≀ 1 ∧ q.degree ≀ 1 ∧ p.coeff 0 * q.coeff 1 - p.coeff 1 * q.coeff 0 = 1} /-- Find all pairs of polynomials $p(x)$ and $q(x)$ with real coefficients for...
putnam_1973_b4
From mathcomp Require Import all_ssreflect ssrnum ssralg. From mathcomp Require Import reals sequences topology measure lebesgue_measure lebesgue_integral normedtype derive. From mathcomp Require Import classical_sets. Import numFieldNormedType.Exports. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Imp...
import Mathlib open Nat Set MeasureTheory Topology Filter -- Note: Boosted domain to ℝ, which is fine because you can extend any such function f from [0,1] to ℝ satisfying the same properties. There may be multiple correct answers. abbrev putnam_1973_b4_solution : ℝ β†’ ℝ := sorry -- (fun x => x) /-- Suppose $f$ is a f...
putnam_1981_a1
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals normedtype sequences topology. From mathcomp Require Import classical_sets. Import numFieldNormedType.Exports. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Local...
import Mathlib open Topology Filter Set Polynomial Function noncomputable abbrev putnam_1981_a1_solution : ℝ := sorry -- 1/8 /-- Let $E(n)$ be the greatest integer $k$ such that $5^k$ divides $1^1 2^2 3^3 \cdots n^n$. Find $\lim_{n \rightarrow \infty} \frac{E(n)}{n^2}$. -/ theorem putnam_1981_a1 (P : β„• β†’ β„• β†’ Prop...
putnam_2005_b1
Require Import Reals Coquelicot.Coquelicot. Definition putnam_2005_b1_solution := (fun x y => match x, y with | 0, 1 => -1 | 0, 2 => 1 | 1, 0 => 2 | 1, 1 => -4 | 2, 0 => 4 | _, _ => 0 end, (2%nat, 2%nat)). Theorem putnam_2005_b1 (p : R -> R -> R := fun x y => sum_n (fun i => (sum_n (fun j => (fst putnam_2005_b1_sol...
import Mathlib open Nat Set -- Note: There might be multiple possible correct answers. noncomputable abbrev putnam_2005_b1_solution : MvPolynomial (Fin 2) ℝ := sorry -- (MvPolynomial.X 1 - 2 * MvPolynomial.X 0) * (MvPolynomial.X 1 - 2 * MvPolynomial.X 0 - 1) /-- Find a nonzero polynomial $P(x,y)$ such that $P(\lfloor...
putnam_1980_b1
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals sequences. From mathcomp Require Import classical_sets. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope classical_set_scope. Local Open Scope ring_scope. Variable R : realType...
import Mathlib open Real abbrev putnam_1980_b1_solution : Set ℝ := sorry -- {c : ℝ | c β‰₯ 1 / 2} /-- For which real numbers $c$ is $(e^x+e^{-x})/2 \leq e^{cx^2}$ for all real $x$? -/ theorem putnam_1980_b1 (c : ℝ) : (βˆ€ x : ℝ, (exp x + exp (-x)) / 2 ≀ exp (c * x ^ 2)) ↔ c ∈ putnam_1980_b1_solution := sorry
putnam_1980_b6
From mathcomp Require Import all_algebra all_ssreflect. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Theorem putnam_1980_b6 (G : (int * int)%type -> rat) (hG : forall d n : nat, leq d n -> ((d = 1%nat -> G (d%:Z, n%:Z) = (1%:Q)/(n%:Q)) /\ (gtn d (1%na...
import Mathlib open Set /-- For integers $d, n$ with $1 \le d \le n$, let $G(1, n) = \frac{1}{n}$ and $G(d, n) = \frac{d}{n}\sum_{i=d}^{n}G(d - 1, i - 1)$ for all $d > 1$. If $1 < d \le p$ for some prime $p$, prove that the reduced denominator of $G(d, p)$ is not divisible by $p$. -/ theorem putnam_1980_b6 (G : β„€ Γ— β„€...
putnam_1962_a2
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals normedtype sequences topology derive measure lebesgue_measure lebesgue_integral. From mathcomp Require Import classical_sets. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ri...
import Mathlib open MeasureTheory Set abbrev putnam_1962_a2_solution : Set (ℝ β†’ ℝ) := sorry -- {f : ℝ β†’ ℝ | βˆƒ a c : ℝ, a β‰₯ 0 ∧ f = fun x ↦ a / (1 - c * x) ^ 2} /-- Find every real-valued function $f$ whose domain is an interval $I$ (finite or infinite) having 0 as a left-hand endpoint, such that for every positive me...
putnam_2015_a2
Require Import Nat Reals Znumtheory BinInt. From mathcomp Require Import div. Definition putnam_2015_a2_solution : nat := 181. Theorem putnam_2015_a2 (A := fix a (n: nat) : Z := match n with | O => 1%Z | S O => 2%Z | S ((S n'') as n') => Z.sub (4*(a n')) (a n'') end) : odd p...
import Mathlib -- Note: this problem admits several possible correct solutions; this is the one shown on the solutions document abbrev putnam_2015_a2_solution : β„• := sorry -- 181 /-- Let $a_0=1$, $a_1=2$, and $a_n=4a_{n-1}-a_{n-2}$ for $n \geq 2$. Find an odd prime factor of $a_{2015}$. -/ theorem putnam_2015_a2 (a : ...
putnam_1990_a2
Require Import Reals Coquelicot.Coquelicot. Open Scope R. Definition putnam_1990_a2_solution := True. Theorem putnam_1990_a2 (numform : R -> Prop := fun x => exists (n m: nat), x = Rpower (INR n) (1/3) - Rpower (INR m) (1/3)) : (exists (s: nat -> R), (forall (i: nat), numform (s i)) /\ is_lim_seq s (sqrt 2)) <-...
import Mathlib open Filter Topology Nat abbrev putnam_1990_a2_solution : Prop := sorry -- True /-- Is $\sqrt{2}$ the limit of a sequence of numbers of the form $\sqrt[3]{n}-\sqrt[3]{m}$ ($n,m=0,1,2,\dots$)? -/ theorem putnam_1990_a2 (numform : ℝ β†’ Prop) (hnumform : βˆ€ x : ℝ, numform x ↔ βˆƒ n m : β„•, x = n ^ ((1 : ℝ)...
putnam_2013_b5
Require Import Basics Reals Ensembles Finite_sets. From mathcomp Require Import fintype. Theorem putnam_2013_b5 (n : nat) (composen := fix compose_n (f : 'I_n -> 'I_n) (n : nat) := match n with | O => fun x => x | S n' => compose f (compose_n f n') end) (k : 'I_n) (npos: ge n...
import Mathlib open Function Set /-- Let $X=\{1,2,\dots,n\}$, and let $k \in X$. Show that there are exactly $k \cdot n^{n-1}$ functions $f:X \to X$ such that for every $x \in X$ there is a $j \geq 0$ such that $f^{(j)}(x) \leq k$. [Here $f^{(j)}$ denotes the $j$\textsuperscript{th} iterate of $f$, so that $f^{(0)}(x...
putnam_2003_b1
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Variable R : realType. Definition putnam_2003_b1_solution : Prop := False. Theorem putnam_2003_b1 : (exists a ...
import Mathlib open MvPolynomial Set abbrev putnam_2003_b1_solution : Prop := sorry -- False /-- Do there exist polynomials $a(x), b(x), c(y), d(y)$ such that \[ 1 + xy + x^2y^2 = a(x)c(y) + b(x)d(y)\] holds identically? -/ theorem putnam_2003_b1 : (βˆƒ a b c d : Polynomial ℝ, (βˆ€ x y : ℝ, 1 + x * y + x ^ 2 * y ^ 2 = a....
putnam_1974_a4
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals sequences exp. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Variable R : realType. Definition putnam_1974_a4_solution : nat -> R := fun n => (n%:R / 2 ^+ (n.-1)...
import Mathlib open Set Nat noncomputable abbrev putnam_1974_a4_solution : β„• β†’ β„š := sorry -- (fun n ↦ (1 : β„š) / (2 ^ (n - 1)) * (n * (n - 1).choose ⌊n / 2βŒ‹β‚Š)) /-- Evaluate in closed form: $\frac{1}{2^{n-1}} \sum_{k < n/2} (n-2k)*{n \choose k}$. -/ theorem putnam_1974_a4 (n : β„•) (hn : 0 < n) : (1 : β„š) / (...
putnam_1985_b3
Require Import Nat Ensembles Finite_sets. Theorem putnam_1985_b3 (a : nat -> nat -> nat) (apos : forall m n : nat, a m n > 0) (ha : forall k : nat, k > 0 -> cardinal (nat * nat) (fun t => let (m, n) := t in m > 0 /\ n > 0 /\ a m n = k) 8) : exists m n : nat, m > 0 /\ n > 0 /\ a m n > m * n. Proof. Admit...
import Mathlib open Set Filter Topology Real Polynomial Function /-- Let \[ \begin{array}{cccc} a_{1,1} & a_{1,2} & a_{1,3} & \dots \\ a_{2,1} & a_{2,2} & a_{2,3} & \dots \\ a_{3,1} & a_{3,2} & a_{3,3} & \dots \\ \vdots & \vdots & \vdots & \ddots \end{array} \] be a doubly infinite array of positive integers, and sup...
putnam_1996_a6
Require Import Reals Coquelicot.Coquelicot. Open Scope R. Definition putnam_1996_a6_solution (c: R) (f: R -> R) := if Rle_dec c (1/4) then (exists (d: R), f = (fun _ => d)) else ((forall (x: R), 0 <= x <= c -> continuity_pt f x) /\ f 0 = f c /\ (forall (x: R), x > 0 -> f x = f (pow x 2 + c)) /\ (forall (x: R), x < 0 -...
import Mathlib open Function abbrev putnam_1996_a6_solution : ℝ β†’ Set (ℝ β†’ ℝ) := sorry -- (fun c : ℝ => if c ≀ 1 / 4 then {f : ℝ β†’ ℝ | βˆƒ d : ℝ, βˆ€ x : ℝ, f x = d} else {f : ℝ β†’ ℝ | ContinuousOn f (Set.Icc 0 c) ∧ f 0 = f c ∧ (βˆ€ x > 0, f x = f (x ^ 2 + c)) ∧ (βˆ€ x < 0, f x = f (-x))}) /-- Let $c>0$ be a constant. Give a ...
putnam_1971_b2
Require Import Reals Ensembles Coquelicot.Coquelicot. Definition putnam_1971_b2_solution : Ensemble (R -> R) := fun f => (f = fun x : R => (x^3 - x^2 - 1)/(2 * x * (x-1))). Theorem putnam_1971_b2 (S : Ensemble R := fun x => x <> 0 /\ x <> 1) (P : (R -> R) -> Prop := fun F => forall x : R, In _ S x -> F x + F ((...
import Mathlib open Set MvPolynomial abbrev putnam_1971_b2_solution : Set (ℝ β†’ ℝ) := sorry -- {fun x : ℝ => (x^3 - x^2 - 1)/(2 * x * (x - 1))} /-- Find all functions $F : \mathbb{R} \setminus \{0, 1\} \to \mathbb{R}$ that satisfy $F(x) + F\left(\frac{x - 1}{x}\right) = 1 + x$ for all $x \in \mathbb{R} \setminus \{0, ...
putnam_1996_a5
Require Import Binomial Reals Znumtheory Coquelicot.Coquelicot. From mathcomp Require Import div. Open Scope R. Theorem putnam_1996_a5 (p : nat) (hp : prime (Z.of_nat p) /\ gt p 3) (k : nat := Z.to_nat (floor (2 * INR p / 3))) : exists (m : nat), sum_n_m (fun i => Binomial.C p i) 1 k = INR m * pow (INR...
import Mathlib open Function /-- If $p$ is a prime number greater than 3 and $k = \lfloor 2p/3 \rfloor$, prove that the sum \[\binom p1 + \binom p2 + \cdots + \binom pk \] of binomial coefficients is divisible by $p^2$. -/ theorem putnam_1996_a5 (p : β„•) (hpprime : Prime p) (hpge3 : p > 3) (k : β„•) (hk : k = Nat.floor ...
putnam_1963_b6
Require Import Ensembles. From GeoCoq Require Import Main.Tarski_dev.Ch16_coordinates_with_functions. (* Note: This formalization assumes a 3D space; 1D and 2D spaces can be seen as lines and planes in this larger space. *) Context `{T3D:Tarski_3D}. Theorem putnam_1963_b6 (T : Ensemble Tpoint -> Ensemble Tpoint := ...
import Mathlib open Topology Filter Polynomial /-- Let $E$ be a Euclidean space of at most three dimensions. If $A$ is a nonempty subset of $E$, define $S(A)$ to be the set of all points that lie on closed segments joining pairs of points of $A$. For a given nonempty set $A_0$, define $A_n=S(A_{n-1})$ for $n=1,2,\dot...
putnam_1978_a5
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals trigo. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Variable R : realType. Theorem putnam_1978_a5 (A : seq R) (hanemp : gt (size A) 0) (ha : all (fu...
import Mathlib open Set Real /-- Let $a_1, a_2, \dots , a_n$ be reals in the interval $(0, \pi)$ with arithmetic mean $\mu$. Show that \[ \prod_{i=1}^n \left( \frac{\sin a_i}{a_i} \right) \leq \left( \frac{\sin \mu}{\mu} \right)^n. \] -/ theorem putnam_1978_a5 (n : β„•) (npos : n > 0) (a : Fin n β†’ ℝ) (ha : βˆ€ i : Fin n,...
putnam_1972_b3
From mathcomp Require Import fingroup. Open Scope group_scope. (* Note: This formalization is only for finite groups (due to mathcomp), but this is sufficiently general since the group generated by A and B is finite. *) Variable T : finGroupType. Theorem putnam_1972_b3 (G : {group T}) (A B : T) (hab : A * B...
import Mathlib open EuclideanGeometry Filter Topology Set MeasureTheory Metric /-- Let $A$ and $B$ be two elements in a group such that $ABA = BA^2B$, $A^3 = 1$, and $B^{2n-1} = 1$ for some positive integer $n$. Prove that $B = 1$. -/ theorem putnam_1972_b3 (G : Type*) [Group G] (A B : G) (hab : A * B * A = B * A^2 *...
putnam_1964_b3
From mathcomp Require Import all_ssreflect all_algebra. From mathcomp Require Import reals sequences normedtype topology. From mathcomp Require Import classical_sets. Import numFieldNormedType.Exports. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Local...
import Mathlib open Set Function Filter Topology /-- Suppose $f : \mathbb{R} \to \mathbb{R}$ is continuous and for every $\alpha > 0$, $\lim_{n \to \infty} f(n\alpha) = 0$. Prove that $\lim_{x \to \infty} f(x) = 0$. -/ theorem putnam_1964_b3 (f : ℝ β†’ ℝ) (hf : Continuous f ∧ βˆ€ Ξ± > 0, Tendsto (fun n : β„• ↦ f (n * Ξ±)) at...
putnam_2000_a2
Require Import Reals. Open Scope Z. Theorem putnam_2000_a2 : forall (m: Z), exists (n: Z), n >= m /\ exists (a1 a2 b1 b2 c1 c2: Z), n = a1*a1 + a2*a2 /\ n+1 = b1*b1 + b2*b2 /\ n+2 = c1*c1 + c2*c2. Proof. Admitted.
import Mathlib open Topology Filter /-- Prove that there exist infinitely many integers $n$ such that $n,n+1,n+2$ are each the sum of the squares of two integers. -/ theorem putnam_2000_a2 : βˆ€ n : β„•, βˆƒ N : β„€, βˆƒ i : Fin 6 β†’ β„•, N > n ∧ N = (i 0)^2 + (i 1)^2 ∧ N + 1 = (i 2)^2 + (i 3)^...
putnam_2001_b3
Require Import Reals Coquelicot.Coquelicot. Definition putnam_2001_b3_solution : R := 3. Theorem putnam_2001_b3 (closest : nat -> R := (fun n : nat => IZR (floor (sqrt (INR n) + 0.5)))) : Series (fun n : nat => sum_n_m (fun n' : nat => (Rpower 2 (closest n') + Rpower 2 (-closest n')) / (2 ^ n')) 1 n) = putnam_2...
import Mathlib open Topology Filter Polynomial Set abbrev putnam_2001_b3_solution : ℝ := sorry -- 3 /-- For any positive integer $n$, let $\langle n \rangle$ denote the closest integer to $\sqrt{n}$. Evaluate $\sum_{n=1}^\infty \frac{2^{\langle n \rangle}+2^{-\langle n \rangle}}{2^n}$. -/ theorem putnam_2001_b3 : βˆ‘' ...
putnam_1985_a6
From mathcomp Require Import all_ssreflect all_algebra. From mathcomp Require Import reals. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Open Scope ring_scope. Variable R : realType. Definition putnam_1985_a6_solution : {poly R} := 6 * 'X ^ 2 + 5 * 'X + 1. Theorem putnam_1985_a6 ...
import Mathlib open Set Filter Topology Real Polynomial noncomputable abbrev putnam_1985_a6_solution : Polynomial ℝ := sorry -- 6 * X ^ 2 + 5 * X + 1 /-- If $p(x)= a_0 + a_1 x + \cdots + a_m x^m$ is a polynomial with real coefficients $a_i$, then set \[ \Gamma(p(x)) = a_0^2 + a_1^2 + \cdots + a_m^2. \] Let $F(x) = 3x...
putnam_1966_a5
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals topology normedtype. From mathcomp Require Import classical_sets. Import numFieldTopology.Exports. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Local Open Scope ...
import Mathlib open Topology Filter /-- Let $C$ be the set of continuous functions $f : \mathbb{R} \to \mathbb{R}$. Let $T : C \to C$ satisfty the following two properties: \begin{enumerate} \item Linearity: $T(af + bg) = aT(f) + bT(g)$ for all $a, b \in \mathbb{R}$ and all $f, g \in C$. \item Locality: If $f \in C$ ...
putnam_2021_b2
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals sequences topology normedtype. From mathcomp Require Import classical_sets. Import numFieldNormedType.Exports. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Local...
import Mathlib open Filter Topology noncomputable abbrev putnam_2021_b2_solution : ℝ := sorry -- 2 / 3 /-- Determine the maximum value of the sum $S = \sum_{n=1}^\infty \frac{n}{2^n}(a_1a_2 \dots a_n)^{1/n}$ over all sequences $a_1,a_2,a_3,\dots$ of nonnegative real numbers satisfying $\sum_{k=1}^\infty a_k=1$. -/ th...
putnam_1988_b3
Require Import Reals Coquelicot.Coquelicot. Definition putnam_1988_b3_solution := (1 + sqrt 3) / 2. Theorem putnam_1988_b3 (r : Z -> R) (hr : forall (n: Z), Z.ge n 1 -> (exists c d : Z, Z.ge c 0 /\ Z.ge d 0 /\ (Z.add c d) = n /\ r n = Rabs (IZR c - IZR d * sqrt 3)) /\ (forall c d : Z, (Z.ge c 0 /\ Z.ge d 0 /\ (...
import Mathlib open Set Filter Topology noncomputable abbrev putnam_1988_b3_solution : ℝ := sorry -- (1 + Real.sqrt 3) / 2 /-- For every $n$ in the set $N=\{1,2,\dots\}$ of positive integers, let $r_n$ be the minimum value of $|c-d \sqrt{3}|$ for all nonnegative integers $c$ and $d$ with $c+d=n$. Find, with proof, th...
putnam_1987_b2
Require Import Binomial Reals Coquelicot.Coquelicot. Theorem putnam_1987_b2 : forall (n r s: nat), ge n (r + s) -> sum_n (fun i => Binomial.C s i / Binomial.C n (r + i)) s = (INR n + 1)/((INR n + 1 - INR s) * Binomial.C (n - s) r). Proof. Admitted.
import Mathlib open MvPolynomial Real Nat /-- Let $r, s$ and $t$ be integers with $0 \leq r$, $0 \leq s$ and $r+s \leq t$. Prove that \[ \frac{\binom s0}{\binom tr} + \frac{\binom s1}{\binom{t}{r+1}} + \cdots + \frac{\binom ss}{\binom{t}{r+s}} = \frac{t+1}{(t+1-s)\binom{t-s}{r}}. \] -/ theorem putnam_1987_b2 (r s t :...
putnam_2003_a2
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals exp sequences normedtype. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Variable R : realType. Theorem putnam_2003_a2 (n : nat) (hn : gt n 0) (a b :...
import Mathlib open MvPolynomial /-- Let $a_1,a_2,\dots,a_n$ and $b_1,b_2,\dots,b_n$ be nonnegative real numbers. Show that $(a_1a_2 \cdots a_n)^{1/n}+(b_1b_2 \cdots b_n)^{1/n} \leq [(a_1+b_1)(a_2+b_2) \cdots (a_n+b_n)]^{1/n}$. -/ theorem putnam_2003_a2 (n : β„•) (hn : 0 < n) (a b : Fin n β†’ ℝ) (abnneg :...
putnam_1980_a5
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals trigo lebesgue_integral lebesgue_measure measure. From mathcomp Require Import classical_sets cardinality. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope classical_set_scope. ...
import Mathlib /-- Let $P(t)$ be a nonconstant polynomial with real coefficients. Prove that the system of simultaneous equations $0=\int_0^xP(t)\sin t\,dt=\int_0^xP(t)\cos t\,dt$ has only finitely many real solutions $x$. -/ theorem putnam_1980_a5 (P : Polynomial ℝ) (Pnonconst : P.degree > 0) : Set.Finite...
putnam_2003_b6
Require Import Reals Coquelicot.Coquelicot. Theorem putnam_2003_b6 (f : R -> R) (hf : continuity f) : RInt (fun x => RInt (fun y => Rabs (f x + f y)) 0 1) 0 1 >= RInt (fun x => Rabs (f x)) 0 1. Proof. Admitted.
import Mathlib open MvPolynomial Set Nat /-- Let $f(x)$ be a continuous real-valued function defined on the interval $[0,1]$. Show that \[ \int_0^1 \int_0^1 | f(x) + f(y) |\,dx\,dy \geq \int_0^1 |f(x)|\,dx. \] -/ theorem putnam_2003_b6 (f : ℝ β†’ ℝ) (hf : Continuous f) : (∫ x in (0 : ℝ)..1, (∫ y in (0 : ℝ)..1, |f x ...
putnam_1985_a3
Require Import Reals Coquelicot.Coquelicot. Open Scope R. Definition putnam_1985_a3_solution (x: R) := exp x - 1. Theorem putnam_1985_a3 (x: R) (A := fix a (i j: nat) := match (i,j) with | (i, 0) => x/pow 2 i | (i, S j') => pow (a i j') 2 + 2 * a i j' end) : Lim_seq (fun n => A...
import Mathlib open Set Filter Topology Real noncomputable abbrev putnam_1985_a3_solution : ℝ β†’ ℝ := sorry -- fun d ↦ exp d - 1 /-- Let $d$ be a real number. For each integer $m \geq 0$, define a sequence $\{a_m(j)\}$, $j=0,1,2,\dots$ by the condition \begin{align*} a_m(0) &= d/2^m, \\ a_m(j+1) &= (a_m(j))^2 + 2a_m(j...
putnam_2021_a5
Require Import Nat. From mathcomp Require Import bigop div fintype eqtype seq ssrbool ssrnat. Variables (I : finType) (P : pred I). Definition putnam_2021_a5_solution (n: nat) := ~ (n %| 42 \/ n %| 46). Theorem putnam_2021_a5 (A : pred 'I_2021 := fun n => let m := nat_of_ord n in ((1 <= m <= 2021) && (gcd m 2021 ...
import Mathlib open Filter Topology abbrev putnam_2021_a5_solution : Set β„• := sorry -- {j : β„• | Β¬(42 ∣ j) ∧ Β¬(46 ∣ j)} /-- Let $A$ be the set of all integers $n$ such that $1 \leq n \leq 2021$ and $\gcd(n,2021)=1$. For every nonnegative integer $j$, let $S(j)=\sum_{n \in A}n^j$. Determine all values of $j$ such that ...
putnam_2019_b2
Require Import Reals Coquelicot.Coquelicot. Definition putnam_2019_b2_solution := 8 / PI ^ 3. Theorem putnam_2019_b2 (a : nat -> R := fun n => sum_n_m (fun k => let k := INR k in let n := INR n in (sin (2 * (k + 1) * PI / (2 * n))) / ((cos ((k - 1) * PI / (2 * n))) ^ 2 * (cos ((k * PI) / (2 * n))) ^ 2)) 1 (n - 1))...
import Mathlib open Topology Filter Set noncomputable abbrev putnam_2019_b2_solution : ℝ := sorry -- 8/Real.pi^3 /-- For all $n \geq 1$, let \[ a_n = \sum_{k=1}^{n-1} \frac{\sin \left( \frac{(2k-1)\pi}{2n} \right)}{\cos^2 \left( \frac{(k-1)\pi}{2n} \right) \cos^2 \left( \frac{k\pi}{2n} \right)}. \] Determine \[ \lim_...
putnam_1993_b5
Require Import ZArith Reals Coquelicot.Coquelicot. From mathcomp Require Import fintype. Theorem putnam_1993_b5 (pdists : ('I_4 -> (R * R)) -> Prop) (hpdists : forall p : 'I_4 -> (R * R), pdists p = (forall i j : 'I_4, i <> j -> (exists k : Z, IZR k = norm (fst (p i) - fst (p j), (snd (p i) - snd (p j))) /\ Z.o...
import Mathlib /-- Show there do not exist four points in the Euclidean plane such that the pairwise distances between the points are all odd integers. -/ theorem putnam_1993_b5: Β¬βˆƒ p : Fin 4 β†’ (EuclideanSpace ℝ (Fin 2)), βˆ€ i j, i β‰  j β†’ (βˆƒ n : β„€, dist (p i) (p j) = n ∧ Odd n) := sorry
putnam_1967_b2
From mathcomp Require Import all_ssreflect all_algebra. From mathcomp Require Import reals normedtype. From mathcomp Require Import classical_sets. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Variable R : realType. Theorem putnam_1967_b2 (p r A ...
import Mathlib open Nat Topology Filter /-- Let $0 \leq p \leq 1$ and $0 \leq r \leq 1$ and consider the identities \begin{enumerate} \item[(a)] $(px+(1-p)y)^2=Ax^2+Bxy+Cy^2$, \item[(b)] $(px+(1-p)y)(rx+(1-r)y)=\alpha x^2+\beta xy+\gamma y^2$. \end{enumerate} Show that (with respect to $p$ and $r$) \begin{enumerate} ...
putnam_2023_b2
Require Import BinNums Nat NArith. Definition putnam_2023_b2_solution := 3. Theorem putnam_2023_b2 (k := fix count_ones (n : positive) : nat := match n with | xH => 1 | xO n' => count_ones n' | xI n' => 1 + count_ones n' end) : (forall (n: nat), n > 0 -> k (Pos.of_nat (2023*n...
import Mathlib open Nat abbrev putnam_2023_b2_solution : β„• := sorry -- 3 /-- For each positive integer $n$, let $k(n)$ be the number of ones in the binary representation of $2023 * n$. What is the minimum value of $k(n)$? -/ theorem putnam_2023_b2 : sInf {(digits 2 (2023*n)).sum | n > 0} = putnam_2023_b2_solution := ...
putnam_1968_b4
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals exp sequences topology normedtype measure lebesgue_measure lebesgue_integral. From mathcomp Require Import classical_sets. Import numFieldNormedType.Exports. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit...
import Mathlib open Finset Polynomial Topology Filter Metric /-- Suppose that $f : \mathbb{R} \to \mathbb{R}$ is continuous on $(-\infty, \infty)$ and that $\int_{-\infty}^{\infty} f(x) dx$ exists. Prove that $$\int_{-\infty}^{\infty} f\left(x - \frac{1}{x}\right) dx = \int_{-\infty}^{\infty} f(x) dx.$$ -/ theorem pu...
putnam_2018_b2
Require Import Reals Coquelicot.Coquelicot. From Coqtail Require Import Cpow. Open Scope C_scope. Theorem putnam_2018_b2 (n : nat) (hn : gt n 0) (f : nat -> C -> C) (hf : forall z : C, f n z = sum_n_m (fun i => (((RtoC (INR n)) - (RtoC (INR i))) * z ^ i)) 0 (n-1)) : forall (z : C), Cnorm z <= 1 -> f...
import Mathlib /-- Let $n$ be a positive integer, and let $f_n(z) = n + (n-1)z + (n-2)z^2 + \cdots + z^{n-1}$. Prove that $f_n$ has no roots in the closed unit disk $\{z \in \mathbb{C}: |z| \leq 1\}$. -/ theorem putnam_2018_b2 (n : β„•) (hn : n > 0) (f : β„• β†’ β„‚ β†’ β„‚) (hf : βˆ€ z : β„‚, f n z = βˆ‘ i ∈ Finset.range n, (n - i) * ...
putnam_2001_a5
Require Import Nat. Theorem putnam_2001_a5 : exists! (a n: nat), a > 0 /\ n > 0 /\ a ^ (n + 1) - (a + 1) ^ n = 2001. Proof. Admitted.
import Mathlib open Topology Filter Polynomial Set /-- Prove that there are unique positive integers $a$, $n$ such that $a^{n+1}-(a+1)^n=2001$. -/ theorem putnam_2001_a5 : βˆƒ! an : β„€ Γ— β„•, let (a, n) := an; a > 0 ∧ n > 0 ∧ a^(n+1) - (a+1)^n = 2001 := sorry
putnam_2016_b6
Require Import List Reals Coquelicot.Hierarchy Coquelicot.Series. Definition putnam_2016_b6_solution := 1. Theorem putnam_2016_b6: Series (fun k => (-1)^k/(INR k+1) * Series (fun n => 1/(INR k*(2^n)+1))) = putnam_2016_b6_solution. Proof. Admitted.
import Mathlib open Polynomial Filter Topology Real Set Nat List abbrev putnam_2016_b6_solution : ℝ := sorry -- 1 /-- Evaluate $\sum_{k=1}^\infty \frac{(-1)^{k-1}}{k} \sum_{n=0}^\infty \frac{1}{k2^n+1}$. -/ theorem putnam_2016_b6 : βˆ‘' k : β„•, ((-1 : ℝ) ^ ((k + 1 : β„€) - 1) / (k + 1 : ℝ)) * βˆ‘' n : β„•, (1 : ℝ) / ((k + 1...
putnam_1974_a6
From mathcomp Require Import all_algebra all_ssreflect. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Definition putnam_1974_a6_solution : nat := 25%nat. Theorem putnam_1974_a6 (hdivnallx : {poly int} -> Prop := fun f => (f \is monic) /\ (forall x ...
import Mathlib open Set Nat Polynomial abbrev putnam_1974_a6_solution : β„• := sorry -- 25 /-- Given $n$, let $k(n)$ be the minimal degree of any monic integral polynomial $f$ such that the value of $f(x)$ is divisible by $n$ for every integer $x$. Find the value of $k(1000000)$. -/ theorem putnam_1974_a6 (hdivnallx : ...
putnam_1984_b1
Require Import Factorial ZArith. Open Scope Z. Fixpoint nat_sum (a : nat -> nat) (k : nat) : nat := match k with | O => a O | S k' => a k + nat_sum a k' end. Fixpoint Z_sum (a : nat -> Z) (k : nat) : Z := match k with | O => a O | S k' => a k + Z_sum a k' end. Definition putnam_1984_b1...
import Mathlib open Topology Filter Nat -- Note: This problem may have multiple correct answers. noncomputable abbrev putnam_1984_b1_solution : Polynomial ℝ Γ— Polynomial ℝ := sorry -- (Polynomial.X + 3, -Polynomial.X - 2) /-- Let $n$ be a positive integer, and define $f(n)=1!+2!+\dots+n!$. Find polynomials $P(x)$ and...
putnam_2006_b2
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Open Scope ring_scope. Variable R : realType. Theorem putnam_2006_b2 (n : nat) (hn : gt n 0) (X : seq R) (hX : uniq X /\ size X...
import Mathlib /-- Prove that, for every set $X = \{x_1, x_2, \dots, x_n\}$ of $n$ real numbers, there exists a non-empty subset $S$ of $X$ and an integer $m$ such that \[ \left| m + \sum_{s \in S} s \right| \leq \frac{1}{n+1}. \] -/ theorem putnam_2006_b2 (n : β„•) (npos : n > 0) (X : Finset ℝ) (hXcard : X.card = n) : ...
putnam_1966_a1
From mathcomp Require Import all_ssreflect ssrnum ssralg ssrint. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Theorem putnam_1966_a1 (f : nat -> int := fun n => \sum_(0 <= m < n + 1) (if (~~odd m) then (m%:Z)/2 else (m%:Z-1)/2)) : forall x y :...
import Mathlib /-- Let $a_n$ denote the sequence $0, 1, 1, 2, 2, 3, \dots$, where $a_n = \frac{n}{2}$ if $n$ is even and $\frac{n - 1}{2}$ if n is odd. Furthermore, let $f(n)$ denote the sum of the first $n$ terms of $a_n$. Prove that all positive integers $x$ and $y$ with $x > y$ satisfy $xy = f(x + y) - f(x - y)$. -...
putnam_2012_a3
Require Import Reals Coquelicot.Coquelicot. Definition putnam_2012_a3_solution (x: R) := sqrt (1 - x ^ 2). Theorem putnam_2012_a3 (hf : (R -> R) -> Prop := fun f : R -> R => continuous_on (fun x : R => -1 <= x <= 1) f /\ (forall x : R, -1 <= x <= 1 -> f x = ((2 - x^2)/2)*f (x^2/(2 - x^2))) /\ f 0 = 1 /\ exists (y :...
import Mathlib open Matrix Function -- Note: uses (ℝ β†’ ℝ) instead of (Set.Icc (-1 : ℝ) 1 β†’ ℝ) noncomputable abbrev putnam_2012_a3_solution : ℝ β†’ ℝ := sorry -- fun x : ℝ => Real.sqrt (1 - x^2) /-- Let $f: [-1, 1] \to \mathbb{R}$ be a continuous function such that \begin{itemize} \item[(i)] $f(x) = \frac{2-x^2}{2} f \l...
putnam_1979_a6
From mathcomp Require Import all_algebra all_ssreflect fintype. From mathcomp Require Import reals. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Variable R : realType. Theorem putnam_1979_b6 (p : seq R) (hp : all (fun x => 0 <= x <= 1) p) ...
import Mathlib open Set /-- For all $i \in \{0, 1, \dots, n - 1\}$, let $p_i \in [0, 1]$. Prove that there exists some $x \in [0, 1]$ such that $$\sum_{i = 0}^{n - 1} \frac{1}{|x - p_i|} \le 8n\left(\sum_{i = 0}^{n-1} \frac{1}{2i + 1}\right).$$ -/ theorem putnam_1979_a6 (n : β„•) (p : β„• β†’ ℝ) (hp : βˆ€ i ∈ Finset.range n,...
putnam_1978_a3
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals measure lebesgue_integral lebesgue_measure topology normedtype exp sequences. From mathcomp Require Import classical_sets. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_...
import Mathlib open Set Polynomial abbrev putnam_1978_a3_solution : β„• := sorry -- 2 /-- Let $p(x) = 2(x^6 + 1) + 4(x^5 + x) + 3(x^4 + x^2) + 5x^3$. For $k$ with $0 < k < 5$, let \[ I_k = \int_0^{\infty} \frac{x^k}{p(x)} \, dx. \] For which $k$ is $I_k$ smallest? -/ theorem putnam_1978_a3 (p : Polynomial ℝ) (h...
putnam_1987_b1
Require Import Reals Coquelicot.Coquelicot. Definition putnam_1987_b1_solution := 1. Theorem putnam_1987_b1 : RInt (fun x => ln (9 - x) ^ (1/2) / ( ln (9 - x) ^ (1/2) + ln (x + 3) ^ (1/2))) 2 4 = putnam_1987_b1_solution. Proof. Admitted.
import Mathlib open MvPolynomial Real Nat abbrev putnam_1987_b1_solution : ℝ := sorry -- 1 /-- Evaluate \[ \int_2^4 \frac{\sqrt{\ln(9-x)}\,dx}{\sqrt{\ln(9-x)}+\sqrt{\ln(x+3)}}. \] -/ theorem putnam_1987_b1 : (∫ x in (2)..4, sqrt (log (9 - x)) / (sqrt (log (9 - x)) + sqrt (log (x + 3))) = putnam_1987_b1_solution) := s...
putnam_1963_a2
From mathcomp Require Import all_algebra all_ssreflect. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope nat_scope. Theorem putnam_1963_a2 (f : nat -> nat) (hfpos : forall n : nat, 0 < f n) (hfinc : forall i j : nat, 0 < i -> i < j -> f i < f j) (hf2 ...
import Mathlib open Topology Filter /-- Let $\{f(n)\}$ be a strictly increasing sequence of positive integers such that $f(2)=2$ and $f(mn)=f(m)f(n)$ for every relatively prime pair of positive integers $m$ and $n$ (the greatest common divisor of $m$ and $n$ is equal to $1$). Prove that $f(n)=n$ for every positive in...
putnam_1962_b2
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals. From mathcomp Require Import classical_sets. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Open Scope ring_scope. Open Scope classical_set_scope. Variable R : realType. Theorem putnam_1962_...
import Mathlib open MeasureTheory --Note: The original problem requires a function to be exhibited, but in the official archives the solution depends on an enumeration of the rationals, so we modify the problem to be an existential statement. /-- Let $\mathbb{S}$ be the set of all subsets of the natural numbers. Prov...
putnam_1975_a1
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals. From mathcomp Require Import classical_sets. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Local Open Scope classical_set_scope. Variable R : realType. Definiti...
import Mathlib open Polynomial abbrev putnam_1975_a1_solution : ((β„€ Γ— β„€) β†’ β„€) Γ— ((β„€ Γ— β„€) β†’ β„€) := sorry -- (fun (a, b) => a + b + 1, fun (a, b) => a - b) /-- If an integer $n$ can be written as the sum of two triangular numbers (that is, $n = \frac{a^2 + a}{2} + \frac{b^2 + b}{2}$ for some integers $a$ and $b$), expre...
putnam_2016_b5
Require Import Reals Rpower. Open Scope R. Definition putnam_2016_b5_solution : (R -> R) -> Prop := fun f => exists (c: R), c > 0 /\ forall (x: R), x > 1 -> f x = Rpower x c . Theorem putnam_2016_b5 (f : R -> R) (fle : Prop := (forall x : R, x > 1 -> f x > 1) /\ (forall x y : R, (x > 1 /\ y > 1 /\ x*x <= y <= x...
import Mathlib open Polynomial Filter Topology Real Set Nat List abbrev putnam_2016_b5_solution : Set (Set.Ioi (1 : ℝ) β†’ Set.Ioi (1 : ℝ)) := sorry -- {f : Set.Ioi (1 : ℝ) β†’ Set.Ioi (1 : ℝ) | βˆƒ c : ℝ, c > 0 ∧ βˆ€ x : Set.Ioi (1 : ℝ), (f x : ℝ) = x ^ c} /-- Find all functions $f$ from the interval $(1,\infty)$ to $(1,\in...
putnam_1964_b5
From mathcomp Require Import all_algebra all_ssreflect. From mathcomp Require Import reals sequences normedtype topology. From mathcomp Require Import classical_sets. Import numFieldNormedType.Exports. Set Implicit Arguments. Unset Strict Implicit. Unset Printing Implicit Defensive. Local Open Scope ring_scope. Local...
import Mathlib open Set Function Filter Topology /-- Let $a_n$ be a strictly monotonic increasing sequence of positive integers. Let $b_n$ be the least common multiple of $a_1, a_2, \dots , a_n$. Prove that $\sum_{n=1}^{\infty} 1/b_n$ converges. -/ theorem putnam_1964_b5 (a b : β„• β†’ β„•) (ha : StrictMono a ∧ βˆ€ n : β„•, a ...
putnam_2010_a6
Require Import Reals Coquelicot.Coquelicot. Theorem putnam_2010_a6 (f: R -> R) (hf : (forall (x: R), x >= 0 -> (forall (y: R), x < y -> f x > f y) /\ continuity_pt f x) /\ is_lim f p_infty 0) : ~ ex_finite_lim (fun nInc => RInt (fun x => (f x - f (x + 1)) / f x) 0 nInc) p_infty. Proof. Admitted.
import Mathlib open Filter Topology Set -- Note: uses (ℝ β†’ ℝ) instead of (Ici 0 β†’ ℝ) /-- Let $f:[0,\infty)\to \mathbb{R}$ be a strictly decreasing continuous function such that $\lim_{x\to\infty} f(x) = 0$. Prove that $\int_0^\infty \frac{f(x)-f(x+1)}{f(x)}\,dx$ diverges. -/ theorem putnam_2010_a6 (f : ℝ β†’ ℝ) (hf : (...
putnam_1989_a2
Require Import Reals Coquelicot.Coquelicot. Open Scope R. Definition putnam_1989_a2_solution (a b: R) := (exp (pow (a*b) 2) - 1)/(a * b). Theorem putnam_1989_a2 (a b: R) (abpos : a > 0 /\ b > 0) (f : R -> R -> R := fun x y => Rmax (pow (b*x) 2) (pow (a*y) 2)) : RInt (fun x => (RInt (fun y => exp (f x y)...
import Mathlib noncomputable abbrev putnam_1989_a2_solution : ℝ β†’ ℝ β†’ ℝ := sorry -- (fun a b : ℝ => (Real.exp (a ^ 2 * b ^ 2) - 1) / (a * b)) /-- Evaluate $\int_0^a \int_0^b e^{\max\{b^2x^2,a^2y^2\}}\,dy\,dx$ where $a$ and $b$ are positive. -/ theorem putnam_1989_a2 (a b : ℝ) (abpos : a > 0 ∧ b > 0) : ∫ x in Set.Ioo 0...
putnam_2015_a5
Require Import Nat Reals Arith Znumtheory Ensembles Finite_sets. Open Scope nat_scope. Theorem putnam_2015_a5 (q : nat) (Nq : nat) (qodd : odd q = true ) (qpos : q > 0) (hNq : cardinal nat (fun a : nat => and (Rle R0 (INR a)) (Rle (INR a) (Rdiv (INR q) (INR 4))) /\ gcd a q = 1) Nq) : odd Nq = t...
import Mathlib /-- Let $q$ be an odd positive integer, and let $N_q$ denote the number of integers $a$ such that $0<a<q/4$ and $\gcd(a,q)=1$. Show that $N_q$ is odd if and only if $q$ is of the form $p^k$ with $k$ a positive integer and $p$ a prime congruent to $5$ or $7$ modulo $8$. -/ theorem putnam_2015_a5 (q : β„•) ...
putnam_2014_a4
From mathcomp.analysis Require Import probability. From mathcomp Require Import all_ssreflect. From mathcomp Require Import ssralg poly ssrnum ssrint interval finmap. From mathcomp Require Import mathcomp_extra boolp classical_sets functions. From mathcomp Require Import cardinality fsbigop. From HB Require Import stru...
import Mathlib open Topology Filter Nat noncomputable abbrev putnam_2014_a4_solution : ℝ := sorry -- 1 / 3 /-- Suppose $X$ is a random variable that takes on only nonnegative integer values, with $E\left[X\right]=1$, $E\left[X^2\right]=2$, and $E\left[X^3\right]=5$. (Here $E\left[Y\right]$ denotes the expectation of ...
putnam_1971_b1
Require Import Ensembles RelationClasses. Theorem putnam_1971_b1 (S : Type) (op : S -> S -> S) (hself : forall x : S, op x x = x) (h2 : forall x y z : S, op (op x y) z = op (op y z) x) : (forall x y z : S, op (op x y) z = op x (op y z)) /\ (forall x y : S, op x y = op y x). Proof. Admitted.
import Mathlib open Set MvPolynomial /-- Let $S$ be a set and let $\cdot$ be a binary operation on $S$ satisfying the two following laws: (1) for all $x$ in $S$, $x = x \cdot x$, (2) for all $x,y,z$ in $S$, $(x \cdot y) \cdot z) = (y \cdot z) \cdot x$. Show that $\cdot$ is associative and commutative. -/ theorem putn...
putnam_1982_a5
Require Import Reals. Open Scope R. Theorem putnam_1982_a5 (a b c d: nat) (hpos : Nat.lt 0 a /\ Nat.lt 0 b /\ Nat.lt 0 c /\ Nat.lt 0 d) (habcd : Nat.le (Nat.add a c) 1982 /\ INR a / INR b + INR c / INR d < 1) : 1 - INR a / INR b - INR c / INR d > 1/pow 1983 3. Proof. Admitted.
import Mathlib /-- Let $a, b, c, d$ be positive integers satisfying $a + c \leq 1982$ and $\frac{a}{b} + \frac{c}{d} < 1$. Prove that $1 - \frac{a}{b} - \frac{c}{d} > \frac{1}{1983^3}$. -/ theorem putnam_1982_a5 (a b c d : β„€) (hpos : a > 0 ∧ b > 0 ∧ c > 0 ∧ d > 0) (hac : a + c ≀ 1982) (hfrac : (a : ℝ) / b + (c : ℝ) / ...
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