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of_add_sum (s : finset ι) (f : ι → α) : of_add (∑ i in s, f i) = ∏ i in s, of_add (f i)
rfl
lemma
of_add_sum
algebra.big_operators
src/algebra/big_operators/basic.lean
[ "algebra.big_operators.multiset.lemmas", "algebra.group.pi", "algebra.group_power.lemmas", "algebra.hom.equiv.basic", "algebra.ring.opposite", "data.finset.sum", "data.fintype.basic", "data.finset.sigma", "data.multiset.powerset", "data.set.pairwise.basic" ]
[ "finset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_add_prod (s : finset ι) (f : ι → multiplicative α) : to_add (∏ i in s, f i) = ∑ i in s, to_add (f i)
rfl
lemma
to_add_prod
algebra.big_operators
src/algebra/big_operators/basic.lean
[ "algebra.big_operators.multiset.lemmas", "algebra.group.pi", "algebra.group_power.lemmas", "algebra.hom.equiv.basic", "algebra.ring.opposite", "data.finset.sum", "data.fintype.basic", "data.finset.sigma", "data.multiset.powerset", "data.set.pairwise.basic" ]
[ "finset", "multiplicative" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_range [comm_monoid β] {n : ℕ} (f : ℕ → β) : ∏ i in finset.range n, f i = ∏ i : fin n, f i
prod_bij' (λ k w, ⟨k, mem_range.mp w⟩) (λ a ha, mem_univ _) (λ a ha, congr_arg _ (fin.coe_mk _).symm) (λ a m, a) (λ a m, mem_range.mpr a.prop) (λ a ha, fin.coe_mk _) (λ a ha, fin.eta _ _)
theorem
finset.prod_range
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid", "fin.coe_mk", "fin.eta", "finset.range" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_univ_def [comm_monoid β] {n : ℕ} (f : fin n → β) : ∏ i, f i = ((list.fin_range n).map f).prod
by simp [univ_def]
theorem
fin.prod_univ_def
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid", "list.fin_range" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_of_fn [comm_monoid β] {n : ℕ} (f : fin n → β) : (list.of_fn f).prod = ∏ i, f i
by rw [list.of_fn_eq_map, prod_univ_def]
theorem
fin.prod_of_fn
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid", "list.of_fn", "list.of_fn_eq_map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_univ_zero [comm_monoid β] (f : fin 0 → β) : ∏ i, f i = 1
rfl
theorem
fin.prod_univ_zero
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid" ]
A product of a function `f : fin 0 → β` is `1` because `fin 0` is empty
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_univ_succ_above [comm_monoid β] {n : ℕ} (f : fin (n + 1) → β) (x : fin (n + 1)) : ∏ i, f i = f x * ∏ i : fin n, f (x.succ_above i)
by rw [univ_succ_above, prod_cons, finset.prod_map, rel_embedding.coe_fn_to_embedding]
theorem
fin.prod_univ_succ_above
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid", "finset.prod_map", "rel_embedding.coe_fn_to_embedding" ]
A product of a function `f : fin (n + 1) → β` over all `fin (n + 1)` is the product of `f x`, for some `x : fin (n + 1)` times the remaining product
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_univ_succ [comm_monoid β] {n : ℕ} (f : fin (n + 1) → β) : ∏ i, f i = f 0 * ∏ i : fin n, f i.succ
prod_univ_succ_above f 0
theorem
fin.prod_univ_succ
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid" ]
A product of a function `f : fin (n + 1) → β` over all `fin (n + 1)` is the product of `f 0` plus the remaining product
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_univ_cast_succ [comm_monoid β] {n : ℕ} (f : fin (n + 1) → β) : ∏ i, f i = (∏ i : fin n, f i.cast_succ) * f (last n)
by simpa [mul_comm] using prod_univ_succ_above f (last n)
theorem
fin.prod_univ_cast_succ
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid", "mul_comm" ]
A product of a function `f : fin (n + 1) → β` over all `fin (n + 1)` is the product of `f (fin.last n)` plus the remaining product
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_cons [comm_monoid β] {n : ℕ} (x : β) (f : fin n → β) : ∏ i : fin n.succ, (cons x f : fin n.succ → β) i = x * ∏ i : fin n, f i
by simp_rw [prod_univ_succ, cons_zero, cons_succ]
lemma
fin.prod_cons
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_univ_one [comm_monoid β] (f : fin 1 → β) : ∏ i, f i = f 0
by simp
theorem
fin.prod_univ_one
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_univ_two [comm_monoid β] (f : fin 2 → β) : ∏ i, f i = f 0 * f 1
by simp [prod_univ_succ]
theorem
fin.prod_univ_two
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_univ_three [comm_monoid β] (f : fin 3 → β) : ∏ i, f i = f 0 * f 1 * f 2
by { rw [prod_univ_cast_succ, prod_univ_two], refl }
theorem
fin.prod_univ_three
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_univ_four [comm_monoid β] (f : fin 4 → β) : ∏ i, f i = f 0 * f 1 * f 2 * f 3
by { rw [prod_univ_cast_succ, prod_univ_three], refl }
theorem
fin.prod_univ_four
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_univ_five [comm_monoid β] (f : fin 5 → β) : ∏ i, f i = f 0 * f 1 * f 2 * f 3 * f 4
by { rw [prod_univ_cast_succ, prod_univ_four], refl }
theorem
fin.prod_univ_five
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_univ_six [comm_monoid β] (f : fin 6 → β) : ∏ i, f i = f 0 * f 1 * f 2 * f 3 * f 4 * f 5
by { rw [prod_univ_cast_succ, prod_univ_five], refl }
theorem
fin.prod_univ_six
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_univ_seven [comm_monoid β] (f : fin 7 → β) : ∏ i, f i = f 0 * f 1 * f 2 * f 3 * f 4 * f 5 * f 6
by { rw [prod_univ_cast_succ, prod_univ_six], refl }
theorem
fin.prod_univ_seven
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_univ_eight [comm_monoid β] (f : fin 8 → β) : ∏ i, f i = f 0 * f 1 * f 2 * f 3 * f 4 * f 5 * f 6 * f 7
by { rw [prod_univ_cast_succ, prod_univ_seven], refl }
theorem
fin.prod_univ_eight
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sum_pow_mul_eq_add_pow {n : ℕ} {R : Type*} [comm_semiring R] (a b : R) : ∑ s : finset (fin n), a ^ s.card * b ^ (n - s.card) = (a + b) ^ n
by simpa using fintype.sum_pow_mul_eq_add_pow (fin n) a b
lemma
fin.sum_pow_mul_eq_add_pow
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_semiring", "finset", "fintype.sum_pow_mul_eq_add_pow" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_const [comm_monoid α] (n : ℕ) (x : α) : ∏ i : fin n, x = x ^ n
by simp
lemma
fin.prod_const
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sum_const [add_comm_monoid α] (n : ℕ) (x : α) : ∑ i : fin n, x = n • x
by simp
lemma
fin.sum_const
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "add_comm_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_Ioi_zero {M : Type*} [comm_monoid M] {n : ℕ} {v : fin n.succ → M} : ∏ i in Ioi 0, v i = ∏ j : fin n, v j.succ
by rw [Ioi_zero_eq_map, finset.prod_map, rel_embedding.coe_fn_to_embedding, coe_succ_embedding]
lemma
fin.prod_Ioi_zero
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid", "finset.prod_map", "rel_embedding.coe_fn_to_embedding" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_Ioi_succ {M : Type*} [comm_monoid M] {n : ℕ} (i : fin n) (v : fin n.succ → M) : ∏ j in Ioi i.succ, v j = ∏ j in Ioi i, v j.succ
by rw [Ioi_succ, finset.prod_map, rel_embedding.coe_fn_to_embedding, coe_succ_embedding]
lemma
fin.prod_Ioi_succ
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid", "finset.prod_map", "rel_embedding.coe_fn_to_embedding" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_congr' {M : Type*} [comm_monoid M] {a b : ℕ} (f : fin b → M) (h : a = b) : ∏ (i : fin a), f (cast h i) = ∏ (i : fin b), f i
by { subst h, congr, ext, congr, ext, rw coe_cast, }
lemma
fin.prod_congr'
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_univ_add {M : Type*} [comm_monoid M] {a b : ℕ} (f : fin (a+b) → M) : ∏ (i : fin (a+b)), f i = (∏ (i : fin a), f (cast_add b i)) * ∏ (i : fin b), f (nat_add a i)
begin rw fintype.prod_equiv fin_sum_fin_equiv.symm f (λ i, f (fin_sum_fin_equiv.to_fun i)), swap, { intro x, simp only [equiv.to_fun_as_coe, equiv.apply_symm_apply], }, apply fintype.prod_sum_type, end
lemma
fin.prod_univ_add
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid", "equiv.apply_symm_apply", "equiv.to_fun_as_coe", "fintype.prod_equiv", "fintype.prod_sum_type" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_trunc {M : Type*} [comm_monoid M] {a b : ℕ} (f : fin (a+b) → M) (hf : ∀ (j : fin b), f (nat_add a j) = 1) : ∏ (i : fin (a+b)), f i = ∏ (i : fin a), f (cast_le (nat.le.intro rfl) i)
by simpa only [prod_univ_add, fintype.prod_eq_one _ hf, mul_one]
lemma
fin.prod_trunc
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_monoid", "fintype.prod_eq_one", "mul_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
partial_prod (f : fin n → α) (i : fin (n + 1)) : α
((list.of_fn f).take i).prod
def
fin.partial_prod
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "list.of_fn" ]
For `f = (a₁, ..., aₙ)` in `αⁿ`, `partial_prod f` is `(1, a₁, a₁a₂, ..., a₁...aₙ)` in `αⁿ⁺¹`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
partial_prod_zero (f : fin n → α) : partial_prod f 0 = 1
by simp [partial_prod]
lemma
fin.partial_prod_zero
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
partial_prod_succ (f : fin n → α) (j : fin n) : partial_prod f j.succ = partial_prod f j.cast_succ * (f j)
by simp [partial_prod, list.take_succ, list.of_fn_nth_val, dif_pos j.is_lt, ←option.coe_def]
lemma
fin.partial_prod_succ
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "list.of_fn_nth_val", "list.take_succ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
partial_prod_succ' (f : fin (n + 1) → α) (j : fin (n + 1)) : partial_prod f j.succ = f 0 * partial_prod (fin.tail f) j
by simpa [partial_prod]
lemma
fin.partial_prod_succ'
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "fin.tail" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
partial_prod_left_inv {G : Type*} [group G] (f : fin (n + 1) → G) : f 0 • partial_prod (λ i : fin n, (f i)⁻¹ * f i.succ) = f
funext $ λ x, fin.induction_on x (by simp) (λ x hx, begin simp only [coe_eq_cast_succ, pi.smul_apply, smul_eq_mul] at hx ⊢, rw [partial_prod_succ, ←mul_assoc, hx, mul_inv_cancel_left], end)
lemma
fin.partial_prod_left_inv
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "fin.induction_on", "group", "mul_inv_cancel_left", "pi.smul_apply", "smul_eq_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
partial_prod_right_inv {G : Type*} [group G] (f : fin n → G) (i : fin n) : (partial_prod f i.cast_succ)⁻¹ * partial_prod f i.succ = f i
begin cases i with i hn, induction i with i hi generalizing hn, { simp [-fin.succ_mk, partial_prod_succ] }, { specialize hi (lt_trans (nat.lt_succ_self i) hn), simp only [fin.coe_eq_cast_succ, fin.succ_mk, fin.cast_succ_mk] at hi ⊢, rw [←fin.succ_mk _ _ (lt_trans (nat.lt_succ_self _) hn), ←fin.succ_mk],...
lemma
fin.partial_prod_right_inv
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "fin.cast_succ_mk", "fin.coe_eq_cast_succ", "fin.succ_mk", "group", "inv_mul_cancel_left", "mul_inv_rev" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv_partial_prod_mul_eq_contract_nth {G : Type*} [group G] (g : fin (n + 1) → G) (j : fin (n + 1)) (k : fin n) : (partial_prod g (j.succ.succ_above k.cast_succ))⁻¹ * partial_prod g (j.succ_above k).succ = j.contract_nth has_mul.mul g k
begin rcases lt_trichotomy (k : ℕ) j with (h|h|h), { rwa [succ_above_below, succ_above_below, partial_prod_right_inv, contract_nth_apply_of_lt], { assumption }, { rw [cast_succ_lt_iff_succ_le, succ_le_succ_iff, le_iff_coe_le_coe], exact le_of_lt h }}, { rwa [succ_above_below, succ_above_above, parti...
lemma
fin.inv_partial_prod_mul_eq_contract_nth
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "group", "inv_mul_cancel_left" ]
Let `(g₀, g₁, ..., gₙ)` be a tuple of elements in `Gⁿ⁺¹`. Then if `k < j`, this says `(g₀g₁...gₖ₋₁)⁻¹ * g₀g₁...gₖ = gₖ`. If `k = j`, it says `(g₀g₁...gₖ₋₁)⁻¹ * g₀g₁...gₖ₊₁ = gₖgₖ₊₁`. If `k > j`, it says `(g₀g₁...gₖ)⁻¹ * g₀g₁...gₖ₊₁ = gₖ₊₁.` Useful for defining group cohomology.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fin_function_fin_equiv {m n : ℕ} : (fin n → fin m) ≃ fin (m ^ n)
equiv.of_right_inverse_of_card_le (le_of_eq $ by simp_rw [fintype.card_fun, fintype.card_fin]) (λ f, ⟨∑ i, f i * m ^ (i : ℕ), begin induction n with n ih generalizing f, { simp }, cases m, { exact is_empty_elim (f $ fin.last _) }, simp_rw [fin.sum_univ_cast_succ, fin.coe_cast_succ, fin.coe_last]...
def
fin_function_fin_equiv
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "equiv.of_right_inverse_of_card_le", "fin.cast", "fin.coe_cast_succ", "fin.coe_last", "fin.coe_mk", "fin.coe_succ", "fin.coe_zero", "fin.ext_iff", "fin.forall_iff", "fin.is_le", "fin.last", "fintype.card_fin", "fintype.card_fun", "ih", "is_empty_elim", "mul_le_mul_right'", "mul_left_...
Equivalence between `fin n → fin m` and `fin (m ^ n)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fin_function_fin_equiv_apply {m n : ℕ} (f : fin n → fin m): (fin_function_fin_equiv f : ℕ) = ∑ (i : fin n), ↑(f i) * m ^ (i : ℕ)
rfl
lemma
fin_function_fin_equiv_apply
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "fin_function_fin_equiv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fin_function_fin_equiv_single {m n : ℕ} [ne_zero m] (i : fin n) (j : fin m) : (fin_function_fin_equiv (pi.single i j) : ℕ) = j * m ^ (i : ℕ)
begin rw [fin_function_fin_equiv_apply, fintype.sum_eq_single i, pi.single_eq_same], rintro x hx, rw [pi.single_eq_of_ne hx, fin.coe_zero, zero_mul], end
lemma
fin_function_fin_equiv_single
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "fin.coe_zero", "fin_function_fin_equiv", "fin_function_fin_equiv_apply", "ne_zero", "zero_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fin_pi_fin_equiv {m : ℕ} {n : fin m → ℕ} : (Π i : fin m, fin (n i)) ≃ fin (∏ i : fin m, n i)
equiv.of_right_inverse_of_card_le (le_of_eq $ by simp_rw [fintype.card_pi, fintype.card_fin]) (λ f, ⟨∑ i, f i * ∏ j, n (fin.cast_le i.is_lt.le j), begin induction m with m ih generalizing f, { simp }, rw [fin.prod_univ_cast_succ, fin.sum_univ_cast_succ], suffices : ∀ (n : fin m → ℕ) (nn : ℕ) (f : Π ...
def
fin_pi_fin_equiv
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "equiv.of_right_inverse_of_card_le", "fin.cast", "fin.cast_le", "fin.coe_mk", "fin.coe_succ", "fin.coe_zero", "fin.cons", "fin.cons_induction", "fin.cons_succ", "fin.cons_zero", "fin.ext_iff", "fin.forall_iff", "fin.init", "fin.init_snoc", "fin.is_le", "fin.is_lt", "fin.last", "fin...
Equivalence between `Π i : fin m, fin (n i)` and `fin (∏ i : fin m, n i)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fin_pi_fin_equiv_apply {m : ℕ} {n : fin m → ℕ} (f : Π i : fin m, fin (n i)): (fin_pi_fin_equiv f : ℕ) = ∑ i, f i * ∏ j, n (fin.cast_le i.is_lt.le j)
rfl
lemma
fin_pi_fin_equiv_apply
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "fin.cast_le", "fin_pi_fin_equiv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fin_pi_fin_equiv_single {m : ℕ} {n : fin m → ℕ} [Π i, ne_zero (n i)] (i : fin m) (j : fin (n i)) : (fin_pi_fin_equiv (pi.single i j : Π i : fin m, fin (n i)) : ℕ) = j * ∏ j, n (fin.cast_le i.is_lt.le j)
begin rw [fin_pi_fin_equiv_apply, fintype.sum_eq_single i, pi.single_eq_same], rintro x hx, rw [pi.single_eq_of_ne hx, fin.coe_zero, zero_mul], end
lemma
fin_pi_fin_equiv_single
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "fin.cast_le", "fin.coe_zero", "fin_pi_fin_equiv", "fin_pi_fin_equiv_apply", "ne_zero", "zero_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_take_of_fn {n : ℕ} (f : fin n → α) (i : ℕ) : ((of_fn f).take i).prod = ∏ j in finset.univ.filter (λ (j : fin n), j.val < i), f j
begin have A : ∀ (j : fin n), ¬ ((j : ℕ) < 0) := λ j, not_lt_bot, induction i with i IH, { simp [A] }, by_cases h : i < n, { have : i < length (of_fn f), by rwa [length_of_fn f], rw prod_take_succ _ _ this, have A : ((finset.univ : finset (fin n)).filter (λ j, j.val < i + 1)) = ((finset.univ : fin...
lemma
list.prod_take_of_fn
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "filter", "finset", "finset.filter", "finset.prod_union", "finset.univ", "nat.lt_succ_iff_lt_or_eq", "not_lt_bot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_of_fn {n : ℕ} {f : fin n → α} : (of_fn f).prod = ∏ i, f i
begin convert prod_take_of_fn f n, { rw [take_all_of_le (le_of_eq (length_of_fn f))] }, { have : ∀ (j : fin n), (j : ℕ) < n := λ j, j.is_lt, simp [this] } end
lemma
list.prod_of_fn
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
alternating_sum_eq_finset_sum {G : Type*} [add_comm_group G] : ∀ (L : list G), alternating_sum L = ∑ i : fin L.length, (-1 : ℤ) ^ (i : ℕ) • L.nth_le i i.is_lt
| [] := by { rw [alternating_sum, finset.sum_eq_zero], rintro ⟨i, ⟨⟩⟩ } | (g :: []) := by simp | (g :: h :: L) := calc g + -h + L.alternating_sum = g + -h + ∑ i : fin L.length, (-1 : ℤ) ^ (i : ℕ) • L.nth_le i i.2 : congr_arg _ (alternating_sum_eq_finset_sum _) ... = ∑ i : fin (L.length + 2), (-1 : ℤ) ^ (i : ℕ...
lemma
list.alternating_sum_eq_finset_sum
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "add_comm_group", "pow_add" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
alternating_prod_eq_finset_prod {G : Type*} [comm_group G] : ∀ (L : list G), alternating_prod L = ∏ i : fin L.length, (L.nth_le i i.2) ^ ((-1 : ℤ) ^ (i : ℕ))
| [] := by { rw [alternating_prod, finset.prod_eq_one], rintro ⟨i, ⟨⟩⟩ } | (g :: []) := begin show g = ∏ i : fin 1, [g].nth_le i i.2 ^ (-1 : ℤ) ^ (i : ℕ), rw [fin.prod_univ_succ], simp, end | (g :: h :: L) := calc g * h⁻¹ * L.alternating_prod = g * h⁻¹ * ∏ i : fin L.length, L.nth_le i i.2 ^ (-1 : ℤ) ^ (i : ℕ) :...
lemma
list.alternating_prod_eq_finset_prod
algebra.big_operators
src/algebra/big_operators/fin.lean
[ "data.fintype.big_operators", "data.fintype.fin", "data.list.fin_range", "logic.equiv.fin" ]
[ "comm_group", "fin.prod_univ_succ", "finset.prod_eq_one", "mul_assoc", "pow_add" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finsum {M α} [add_comm_monoid M] (f : α → M) : M
if h : (support (f ∘ plift.down)).finite then ∑ i in h.to_finset, f i.down else 0
def
finsum
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "add_comm_monoid", "finite" ]
Sum of `f x` as `x` ranges over the elements of the support of `f`, if it's finite. Zero otherwise.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod (f : α → M) : M
if h : (mul_support (f ∘ plift.down)).finite then ∏ i in h.to_finset, f i.down else 1
def
finprod
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finite" ]
Product of `f x` as `x` ranges over the elements of the multiplicative support of `f`, if it's finite. One otherwise.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_eq_prod_plift_of_mul_support_to_finset_subset {f : α → M} (hf : (mul_support (f ∘ plift.down)).finite) {s : finset (plift α)} (hs : hf.to_finset ⊆ s) : ∏ᶠ i, f i = ∏ i in s, f i.down
begin rw [finprod, dif_pos], refine finset.prod_subset hs (λ x hx hxf, _), rwa [hf.mem_to_finset, nmem_mul_support] at hxf end
lemma
finprod_eq_prod_plift_of_mul_support_to_finset_subset
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finite", "finprod", "finset", "finset.prod_subset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_eq_prod_plift_of_mul_support_subset {f : α → M} {s : finset (plift α)} (hs : mul_support (f ∘ plift.down) ⊆ s) : ∏ᶠ i, f i = ∏ i in s, f i.down
finprod_eq_prod_plift_of_mul_support_to_finset_subset (s.finite_to_set.subset hs) $ λ x hx, by { rw finite.mem_to_finset at hx, exact hs hx }
lemma
finprod_eq_prod_plift_of_mul_support_subset
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_eq_prod_plift_of_mul_support_to_finset_subset", "finset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_one : ∏ᶠ i : α, (1 : M) = 1
begin have : mul_support (λ x : plift α, (λ _, 1 : α → M) x.down) ⊆ (∅ : finset (plift α)), from λ x h, h rfl, rw [finprod_eq_prod_plift_of_mul_support_subset this, finset.prod_empty] end
lemma
finprod_one
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_eq_prod_plift_of_mul_support_subset", "finset", "finset.prod_empty" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_of_is_empty [is_empty α] (f : α → M) : ∏ᶠ i, f i = 1
by { rw ← finprod_one, congr }
lemma
finprod_of_is_empty
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_one", "is_empty" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_false (f : false → M) : ∏ᶠ i, f i = 1
finprod_of_is_empty _
lemma
finprod_false
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_of_is_empty" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_eq_single (f : α → M) (a : α) (ha : ∀ x ≠ a, f x = 1) : ∏ᶠ x, f x = f a
begin have : mul_support (f ∘ plift.down) ⊆ ({plift.up a} : finset (plift α)), { intro x, contrapose, simpa [plift.eq_up_iff_down_eq] using ha x.down }, rw [finprod_eq_prod_plift_of_mul_support_subset this, finset.prod_singleton], end
lemma
finprod_eq_single
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_eq_prod_plift_of_mul_support_subset", "finset", "finset.prod_singleton", "plift.eq_up_iff_down_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_unique [unique α] (f : α → M) : ∏ᶠ i, f i = f default
finprod_eq_single f default $ λ x hx, (hx $ unique.eq_default _).elim
lemma
finprod_unique
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_eq_single", "unique", "unique.eq_default" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_true (f : true → M) : ∏ᶠ i, f i = f trivial
@finprod_unique M true _ ⟨⟨trivial⟩, λ _, rfl⟩ f
lemma
finprod_true
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_unique" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_eq_dif {p : Prop} [decidable p] (f : p → M) : ∏ᶠ i, f i = if h : p then f h else 1
begin split_ifs, { haveI : unique p := ⟨⟨h⟩, λ _, rfl⟩, exact finprod_unique f }, { haveI : is_empty p := ⟨h⟩, exact finprod_of_is_empty f } end
lemma
finprod_eq_dif
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_of_is_empty", "finprod_unique", "is_empty", "unique" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_eq_if {p : Prop} [decidable p] {x : M} : ∏ᶠ i : p, x = if p then x else 1
finprod_eq_dif (λ _, x)
lemma
finprod_eq_if
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_eq_dif" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_congr {f g : α → M} (h : ∀ x, f x = g x) : finprod f = finprod g
congr_arg _ $ funext h
lemma
finprod_congr
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_congr_Prop {p q : Prop} {f : p → M} {g : q → M} (hpq : p = q) (hfg : ∀ h : q, f (hpq.mpr h) = g h) : finprod f = finprod g
by { subst q, exact finprod_congr hfg }
lemma
finprod_congr_Prop
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod", "finprod_congr" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_induction {f : α → M} (p : M → Prop) (hp₀ : p 1) (hp₁ : ∀ x y, p x → p y → p (x * y)) (hp₂ : ∀ i, p (f i)) : p (∏ᶠ i, f i)
begin rw finprod, split_ifs, exacts [finset.prod_induction _ _ hp₁ hp₀ (λ i hi, hp₂ _), hp₀] end
lemma
finprod_induction
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod", "finset.prod_induction" ]
To prove a property of a finite product, it suffices to prove that the property is multiplicative and holds on the factors.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_nonneg {R : Type*} [ordered_comm_semiring R] {f : α → R} (hf : ∀ x, 0 ≤ f x) : 0 ≤ ∏ᶠ x, f x
finprod_induction (λ x, 0 ≤ x) zero_le_one (λ x y, mul_nonneg) hf
lemma
finprod_nonneg
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_induction", "ordered_comm_semiring", "zero_le_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one_le_finprod' {M : Type*} [ordered_comm_monoid M] {f : α → M} (hf : ∀ i, 1 ≤ f i) : 1 ≤ ∏ᶠ i, f i
finprod_induction _ le_rfl (λ _ _, one_le_mul) hf
lemma
one_le_finprod'
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_induction", "le_rfl", "ordered_comm_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
monoid_hom.map_finprod_plift (f : M →* N) (g : α → M) (h : (mul_support $ g ∘ plift.down).finite) : f (∏ᶠ x, g x) = ∏ᶠ x, f (g x)
begin rw [finprod_eq_prod_plift_of_mul_support_subset h.coe_to_finset.ge, finprod_eq_prod_plift_of_mul_support_subset, f.map_prod], rw [h.coe_to_finset], exact mul_support_comp_subset f.map_one (g ∘ plift.down) end
lemma
monoid_hom.map_finprod_plift
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finite", "finprod_eq_prod_plift_of_mul_support_subset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
monoid_hom.map_finprod_Prop {p : Prop} (f : M →* N) (g : p → M) : f (∏ᶠ x, g x) = ∏ᶠ x, f (g x)
f.map_finprod_plift g (set.to_finite _)
lemma
monoid_hom.map_finprod_Prop
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "set.to_finite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
monoid_hom.map_finprod_of_preimage_one (f : M →* N) (hf : ∀ x, f x = 1 → x = 1) (g : α → M) : f (∏ᶠ i, g i) = ∏ᶠ i, f (g i)
begin by_cases hg : (mul_support $ g ∘ plift.down).finite, { exact f.map_finprod_plift g hg }, rw [finprod, dif_neg, f.map_one, finprod, dif_neg], exacts [infinite.mono (λ x hx, mt (hf (g x.down)) hx) hg, hg] end
lemma
monoid_hom.map_finprod_of_preimage_one
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finite", "finprod" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
monoid_hom.map_finprod_of_injective (g : M →* N) (hg : injective g) (f : α → M) : g (∏ᶠ i, f i) = ∏ᶠ i, g (f i)
g.map_finprod_of_preimage_one (λ x, (hg.eq_iff' g.map_one).mp) f
lemma
monoid_hom.map_finprod_of_injective
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_equiv.map_finprod (g : M ≃* N) (f : α → M) : g (∏ᶠ i, f i) = ∏ᶠ i, g (f i)
g.to_monoid_hom.map_finprod_of_injective g.injective f
lemma
mul_equiv.map_finprod
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finsum_smul {R M : Type*} [ring R] [add_comm_group M] [module R M] [no_zero_smul_divisors R M] (f : ι → R) (x : M) : (∑ᶠ i, f i) • x = ∑ᶠ i, f i • x
begin rcases eq_or_ne x 0 with rfl|hx, { simp }, exact ((smul_add_hom R M).flip x).map_finsum_of_injective (smul_left_injective R hx) _ end
lemma
finsum_smul
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "add_comm_group", "eq_or_ne", "module", "no_zero_smul_divisors", "ring", "smul_add_hom", "smul_left_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
smul_finsum {R M : Type*} [ring R] [add_comm_group M] [module R M] [no_zero_smul_divisors R M] (c : R) (f : ι → M) : c • (∑ᶠ i, f i) = (∑ᶠ i, c • f i)
begin rcases eq_or_ne c 0 with rfl|hc, { simp }, exact (smul_add_hom R M c).map_finsum_of_injective (smul_right_injective M hc) _ end
lemma
smul_finsum
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "add_comm_group", "eq_or_ne", "module", "no_zero_smul_divisors", "ring", "smul_add_hom", "smul_right_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_inv_distrib [division_comm_monoid G] (f : α → G) : ∏ᶠ x, (f x)⁻¹ = (∏ᶠ x, f x)⁻¹
((mul_equiv.inv G).map_finprod f).symm
lemma
finprod_inv_distrib
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "division_comm_monoid", "mul_equiv.inv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_eq_mul_indicator_apply (s : set α) (f : α → M) (a : α) : ∏ᶠ (h : a ∈ s), f a = mul_indicator s f a
by convert finprod_eq_if
lemma
finprod_eq_mul_indicator_apply
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_eq_if" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mem_mul_support (f : α → M) (a : α) : ∏ᶠ (h : f a ≠ 1), f a = f a
by rw [← mem_mul_support, finprod_eq_mul_indicator_apply, mul_indicator_mul_support]
lemma
finprod_mem_mul_support
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_eq_mul_indicator_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mem_def (s : set α) (f : α → M) : ∏ᶠ a ∈ s, f a = ∏ᶠ a, mul_indicator s f a
finprod_congr $ finprod_eq_mul_indicator_apply s f
lemma
finprod_mem_def
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_congr", "finprod_eq_mul_indicator_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_eq_prod_of_mul_support_subset (f : α → M) {s : finset α} (h : mul_support f ⊆ s) : ∏ᶠ i, f i = ∏ i in s, f i
begin have A : mul_support (f ∘ plift.down) = equiv.plift.symm '' mul_support f, { rw mul_support_comp_eq_preimage, exact (equiv.plift.symm.image_eq_preimage _).symm }, have : mul_support (f ∘ plift.down) ⊆ s.map equiv.plift.symm.to_embedding, { rw [A, finset.coe_map], exact image_subset _ h }, rw [finpro...
lemma
finprod_eq_prod_of_mul_support_subset
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_eq_prod_plift_of_mul_support_subset", "finset", "finset.coe_map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_eq_prod_of_mul_support_to_finset_subset (f : α → M) (hf : (mul_support f).finite) {s : finset α} (h : hf.to_finset ⊆ s) : ∏ᶠ i, f i = ∏ i in s, f i
finprod_eq_prod_of_mul_support_subset _ $ λ x hx, h $ hf.mem_to_finset.2 hx
lemma
finprod_eq_prod_of_mul_support_to_finset_subset
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finite", "finprod_eq_prod_of_mul_support_subset", "finset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_eq_finset_prod_of_mul_support_subset (f : α → M) {s : finset α} (h : mul_support f ⊆ (s : set α)) : ∏ᶠ i, f i = ∏ i in s, f i
begin have h' : (s.finite_to_set.subset h).to_finset ⊆ s, { simpa [← finset.coe_subset, set.coe_to_finset], }, exact finprod_eq_prod_of_mul_support_to_finset_subset _ _ h', end
lemma
finprod_eq_finset_prod_of_mul_support_subset
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_eq_prod_of_mul_support_to_finset_subset", "finset", "finset.coe_subset", "set.coe_to_finset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_def (f : α → M) [decidable (mul_support f).finite] : ∏ᶠ i : α, f i = if h : (mul_support f).finite then ∏ i in h.to_finset, f i else 1
begin split_ifs, { exact finprod_eq_prod_of_mul_support_to_finset_subset _ h (finset.subset.refl _) }, { rw [finprod, dif_neg], rw [mul_support_comp_eq_preimage], exact mt (λ hf, hf.of_preimage equiv.plift.surjective) h} end
lemma
finprod_def
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finite", "finprod", "finprod_eq_prod_of_mul_support_to_finset_subset", "finset.subset.refl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_of_infinite_mul_support {f : α → M} (hf : (mul_support f).infinite) : ∏ᶠ i, f i = 1
by { classical, rw [finprod_def, dif_neg hf] }
lemma
finprod_of_infinite_mul_support
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_def", "infinite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_eq_prod (f : α → M) (hf : (mul_support f).finite) : ∏ᶠ i : α, f i = ∏ i in hf.to_finset, f i
by { classical, rw [finprod_def, dif_pos hf] }
lemma
finprod_eq_prod
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finite", "finprod_def" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_eq_prod_of_fintype [fintype α] (f : α → M) : ∏ᶠ i : α, f i = ∏ i, f i
finprod_eq_prod_of_mul_support_to_finset_subset _ (set.to_finite _) $ finset.subset_univ _
lemma
finprod_eq_prod_of_fintype
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_eq_prod_of_mul_support_to_finset_subset", "finset.subset_univ", "fintype", "set.to_finite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_cond_eq_prod_of_cond_iff (f : α → M) {p : α → Prop} {t : finset α} (h : ∀ {x}, f x ≠ 1 → (p x ↔ x ∈ t)) : ∏ᶠ i (hi : p i), f i = ∏ i in t, f i
begin set s := {x | p x}, have : mul_support (s.mul_indicator f) ⊆ t, { rw [set.mul_support_mul_indicator], intros x hx, exact (h hx.2).1 hx.1 }, erw [finprod_mem_def, finprod_eq_prod_of_mul_support_subset _ this], refine finset.prod_congr rfl (λ x hx, mul_indicator_apply_eq_self.2 $ λ hxs, _), contrapose! ...
lemma
finprod_cond_eq_prod_of_cond_iff
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_eq_prod_of_mul_support_subset", "finprod_mem_def", "finset", "finset.prod_congr", "set.mul_support_mul_indicator" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_cond_ne (f : α → M) (a : α) [decidable_eq α] (hf : (mul_support f).finite) : (∏ᶠ i ≠ a, f i) = ∏ i in hf.to_finset.erase a, f i
begin apply finprod_cond_eq_prod_of_cond_iff, intros x hx, rw [finset.mem_erase, finite.mem_to_finset, mem_mul_support], exact ⟨λ h, and.intro h hx, λ h, h.1⟩ end
lemma
finprod_cond_ne
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finite", "finprod_cond_eq_prod_of_cond_iff", "finset.mem_erase" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mem_eq_prod_of_inter_mul_support_eq (f : α → M) {s : set α} {t : finset α} (h : s ∩ mul_support f = t ∩ mul_support f) : ∏ᶠ i ∈ s, f i = ∏ i in t, f i
finprod_cond_eq_prod_of_cond_iff _ $ by simpa [set.ext_iff] using h
lemma
finprod_mem_eq_prod_of_inter_mul_support_eq
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_cond_eq_prod_of_cond_iff", "finset", "set.ext_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mem_eq_prod_of_subset (f : α → M) {s : set α} {t : finset α} (h₁ : s ∩ mul_support f ⊆ t) (h₂ : ↑t ⊆ s) : ∏ᶠ i ∈ s, f i = ∏ i in t, f i
finprod_cond_eq_prod_of_cond_iff _ $ λ x hx, ⟨λ h, h₁ ⟨h, hx⟩, λ h, h₂ h⟩
lemma
finprod_mem_eq_prod_of_subset
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_cond_eq_prod_of_cond_iff", "finset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mem_eq_prod (f : α → M) {s : set α} (hf : (s ∩ mul_support f).finite) : ∏ᶠ i ∈ s, f i = ∏ i in hf.to_finset, f i
finprod_mem_eq_prod_of_inter_mul_support_eq _ $ by simp [inter_assoc]
lemma
finprod_mem_eq_prod
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finite", "finprod_mem_eq_prod_of_inter_mul_support_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mem_eq_prod_filter (f : α → M) (s : set α) [decidable_pred (∈ s)] (hf : (mul_support f).finite) : ∏ᶠ i ∈ s, f i = ∏ i in finset.filter (∈ s) hf.to_finset, f i
finprod_mem_eq_prod_of_inter_mul_support_eq _ $ by simp [inter_comm, inter_left_comm]
lemma
finprod_mem_eq_prod_filter
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finite", "finprod_mem_eq_prod_of_inter_mul_support_eq", "finset.filter" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mem_eq_to_finset_prod (f : α → M) (s : set α) [fintype s] : ∏ᶠ i ∈ s, f i = ∏ i in s.to_finset, f i
finprod_mem_eq_prod_of_inter_mul_support_eq _ $ by rw [coe_to_finset]
lemma
finprod_mem_eq_to_finset_prod
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_mem_eq_prod_of_inter_mul_support_eq", "fintype" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mem_eq_finite_to_finset_prod (f : α → M) {s : set α} (hs : s.finite) : ∏ᶠ i ∈ s, f i = ∏ i in hs.to_finset, f i
finprod_mem_eq_prod_of_inter_mul_support_eq _ $ by rw [hs.coe_to_finset]
lemma
finprod_mem_eq_finite_to_finset_prod
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_mem_eq_prod_of_inter_mul_support_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mem_finset_eq_prod (f : α → M) (s : finset α) : ∏ᶠ i ∈ s, f i = ∏ i in s, f i
finprod_mem_eq_prod_of_inter_mul_support_eq _ rfl
lemma
finprod_mem_finset_eq_prod
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_mem_eq_prod_of_inter_mul_support_eq", "finset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mem_coe_finset (f : α → M) (s : finset α) : ∏ᶠ i ∈ (s : set α), f i = ∏ i in s, f i
finprod_mem_eq_prod_of_inter_mul_support_eq _ rfl
lemma
finprod_mem_coe_finset
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_mem_eq_prod_of_inter_mul_support_eq", "finset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mem_eq_one_of_infinite {f : α → M} {s : set α} (hs : (s ∩ mul_support f).infinite) : ∏ᶠ i ∈ s, f i = 1
begin rw finprod_mem_def, apply finprod_of_infinite_mul_support, rwa [← mul_support_mul_indicator] at hs end
lemma
finprod_mem_eq_one_of_infinite
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_mem_def", "finprod_of_infinite_mul_support", "infinite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mem_eq_one_of_forall_eq_one {f : α → M} {s : set α} (h : ∀ x ∈ s, f x = 1) : ∏ᶠ i ∈ s, f i = 1
by simp [h] {contextual := tt}
lemma
finprod_mem_eq_one_of_forall_eq_one
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mem_inter_mul_support (f : α → M) (s : set α) : ∏ᶠ i ∈ (s ∩ mul_support f), f i = ∏ᶠ i ∈ s, f i
by rw [finprod_mem_def, finprod_mem_def, mul_indicator_inter_mul_support]
lemma
finprod_mem_inter_mul_support
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_mem_def" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mem_inter_mul_support_eq (f : α → M) (s t : set α) (h : s ∩ mul_support f = t ∩ mul_support f) : ∏ᶠ i ∈ s, f i = ∏ᶠ i ∈ t, f i
by rw [← finprod_mem_inter_mul_support, h, finprod_mem_inter_mul_support]
lemma
finprod_mem_inter_mul_support_eq
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_mem_inter_mul_support" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mem_inter_mul_support_eq' (f : α → M) (s t : set α) (h : ∀ x ∈ mul_support f, x ∈ s ↔ x ∈ t) : ∏ᶠ i ∈ s, f i = ∏ᶠ i ∈ t, f i
begin apply finprod_mem_inter_mul_support_eq, ext x, exact and_congr_left (h x) end
lemma
finprod_mem_inter_mul_support_eq'
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "and_congr_left", "finprod_mem_inter_mul_support_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mem_univ (f : α → M) : ∏ᶠ i ∈ @set.univ α, f i = ∏ᶠ i : α, f i
finprod_congr $ λ i, finprod_true _
lemma
finprod_mem_univ
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_congr", "finprod_true" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mem_congr (h₀ : s = t) (h₁ : ∀ x ∈ t, f x = g x) : ∏ᶠ i ∈ s, f i = ∏ᶠ i ∈ t, g i
h₀.symm ▸ (finprod_congr $ λ i, finprod_congr_Prop rfl (h₁ i))
lemma
finprod_mem_congr
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finprod_congr", "finprod_congr_Prop" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_eq_one_of_forall_eq_one {f : α → M} (h : ∀ x, f x = 1) : ∏ᶠ i, f i = 1
by simp [h] {contextual := tt}
lemma
finprod_eq_one_of_forall_eq_one
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mul_distrib (hf : (mul_support f).finite) (hg : (mul_support g).finite) : ∏ᶠ i, f i * g i = (∏ᶠ i, f i) * ∏ᶠ i, g i
begin classical, rw [finprod_eq_prod_of_mul_support_to_finset_subset _ hf (finset.subset_union_left _ _), finprod_eq_prod_of_mul_support_to_finset_subset _ hg (finset.subset_union_right _ _), ← finset.prod_mul_distrib], refine finprod_eq_prod_of_mul_support_subset _ _, simp [mul_support_mul] end
lemma
finprod_mul_distrib
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finite", "finprod_eq_prod_of_mul_support_subset", "finprod_eq_prod_of_mul_support_to_finset_subset", "finset.prod_mul_distrib", "finset.subset_union_left", "finset.subset_union_right" ]
If the multiplicative supports of `f` and `g` are finite, then the product of `f i * g i` equals the product of `f i` multiplied by the product of `g i`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_div_distrib [division_comm_monoid G] {f g : α → G} (hf : (mul_support f).finite) (hg : (mul_support g).finite) : ∏ᶠ i, f i / g i = (∏ᶠ i, f i) / ∏ᶠ i, g i
by simp only [div_eq_mul_inv, finprod_mul_distrib hf ((mul_support_inv g).symm.rec hg), finprod_inv_distrib]
lemma
finprod_div_distrib
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "div_eq_mul_inv", "division_comm_monoid", "finite", "finprod_inv_distrib", "finprod_mul_distrib" ]
If the multiplicative supports of `f` and `g` are finite, then the product of `f i / g i` equals the product of `f i` divided by the product of `g i`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mem_mul_distrib' (hf : (s ∩ mul_support f).finite) (hg : (s ∩ mul_support g).finite) : ∏ᶠ i ∈ s, f i * g i = (∏ᶠ i ∈ s, f i) * ∏ᶠ i ∈ s, g i
begin rw [← mul_support_mul_indicator] at hf hg, simp only [finprod_mem_def, mul_indicator_mul, finprod_mul_distrib hf hg] end
lemma
finprod_mem_mul_distrib'
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[ "finite", "finprod_mem_def", "finprod_mul_distrib" ]
A more general version of `finprod_mem_mul_distrib` that only requires `s ∩ mul_support f` and `s ∩ mul_support g` rather than `s` to be finite.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finprod_mem_one (s : set α) : ∏ᶠ i ∈ s, (1 : M) = 1
by simp
lemma
finprod_mem_one
algebra.big_operators
src/algebra/big_operators/finprod.lean
[ "algebra.big_operators.order", "algebra.indicator_function" ]
[]
The product of the constant function `1` over any set equals `1`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83