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coe_stream_nth_rat_eq : ((int_fract_pair.stream q n).map (mapFr coe) : option $ int_fract_pair K) = int_fract_pair.stream v n
begin induction n with n IH, case nat.zero : { simp [int_fract_pair.stream, (coe_of_rat_eq v_eq_q)] }, case nat.succ : { rw v_eq_q at IH, cases stream_q_nth_eq : (int_fract_pair.stream q n) with ifp_n, case option.none : { simp [int_fract_pair.stream, IH.symm, v_eq_q, stream_q_nth_eq] }, case option...
lemma
generalized_continued_fraction.int_fract_pair.coe_stream_nth_rat_eq
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/terminates_iff_rat.lean
[ "algebra.continued_fractions.computation.approximations", "algebra.continued_fractions.computation.correctness_terminating", "data.rat.floor" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_stream_rat_eq : ((int_fract_pair.stream q).map (option.map (mapFr coe)) : stream $ option $ int_fract_pair K) = int_fract_pair.stream v
by { funext n, exact (int_fract_pair.coe_stream_nth_rat_eq v_eq_q n) }
lemma
generalized_continued_fraction.int_fract_pair.coe_stream_rat_eq
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/terminates_iff_rat.lean
[ "algebra.continued_fractions.computation.approximations", "algebra.continued_fractions.computation.correctness_terminating", "data.rat.floor" ]
[ "stream" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_of_h_rat_eq : (↑((of q).h : ℚ) : K) = (of v).h
begin unfold of int_fract_pair.seq1, rw ←(int_fract_pair.coe_of_rat_eq v_eq_q), simp end
lemma
generalized_continued_fraction.coe_of_h_rat_eq
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/terminates_iff_rat.lean
[ "algebra.continued_fractions.computation.approximations", "algebra.continued_fractions.computation.correctness_terminating", "data.rat.floor" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_of_s_nth_rat_eq : (((of q).s.nth n).map (pair.map coe) : option $ pair K) = (of v).s.nth n
begin simp only [of, int_fract_pair.seq1, seq.map_nth, seq.nth_tail], simp only [seq.nth], rw [←(int_fract_pair.coe_stream_rat_eq v_eq_q)], rcases succ_nth_stream_eq : (int_fract_pair.stream q (n + 1)) with _ | ⟨_, _⟩; simp [stream.map, stream.nth, succ_nth_stream_eq] end
lemma
generalized_continued_fraction.coe_of_s_nth_rat_eq
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/terminates_iff_rat.lean
[ "algebra.continued_fractions.computation.approximations", "algebra.continued_fractions.computation.correctness_terminating", "data.rat.floor" ]
[ "stream.map", "stream.nth" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_of_s_rat_eq : (((of q).s).map (pair.map coe) : seq $ pair K) = (of v).s
by { ext n, rw ←(coe_of_s_nth_rat_eq v_eq_q), refl }
lemma
generalized_continued_fraction.coe_of_s_rat_eq
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/terminates_iff_rat.lean
[ "algebra.continued_fractions.computation.approximations", "algebra.continued_fractions.computation.correctness_terminating", "data.rat.floor" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_of_rat_eq : (⟨(of q).h, (of q).s.map (pair.map coe)⟩ : generalized_continued_fraction K) = of v
begin cases gcf_v_eq : (of v) with h s, subst v, obtain rfl : ↑⌊↑q⌋ = h, by { injection gcf_v_eq }, simp [coe_of_h_rat_eq rfl, coe_of_s_rat_eq rfl, gcf_v_eq] end
lemma
generalized_continued_fraction.coe_of_rat_eq
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/terminates_iff_rat.lean
[ "algebra.continued_fractions.computation.approximations", "algebra.continued_fractions.computation.correctness_terminating", "data.rat.floor" ]
[ "generalized_continued_fraction" ]
Given `(v : K), (q : ℚ), and v = q`, we have that `gcf.of q = gcf.of v`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_terminates_iff_of_rat_terminates {v : K} {q : ℚ} (v_eq_q : v = (q : K)) : (of v).terminates ↔ (of q).terminates
begin split; intro h; cases h with n h; use n; simp only [seq.terminated_at, (coe_of_s_nth_rat_eq v_eq_q n).symm] at h ⊢; cases ((of q).s.nth n); trivial end
lemma
generalized_continued_fraction.of_terminates_iff_of_rat_terminates
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/terminates_iff_rat.lean
[ "algebra.continued_fractions.computation.approximations", "algebra.continued_fractions.computation.correctness_terminating", "data.rat.floor" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_inv_fr_num_lt_num_of_pos (q_pos : 0 < q) : (int_fract_pair.of q⁻¹).fr.num < q.num
rat.fract_inv_num_lt_num_of_pos q_pos
lemma
generalized_continued_fraction.int_fract_pair.of_inv_fr_num_lt_num_of_pos
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/terminates_iff_rat.lean
[ "algebra.continued_fractions.computation.approximations", "algebra.continued_fractions.computation.correctness_terminating", "data.rat.floor" ]
[ "rat.fract_inv_num_lt_num_of_pos" ]
Shows that for any `q : ℚ` with `0 < q < 1`, the numerator of the fractional part of `int_fract_pair.of q⁻¹` is smaller than the numerator of `q`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
stream_succ_nth_fr_num_lt_nth_fr_num_rat {ifp_n ifp_succ_n : int_fract_pair ℚ} (stream_nth_eq : int_fract_pair.stream q n = some ifp_n) (stream_succ_nth_eq : int_fract_pair.stream q (n + 1) = some ifp_succ_n) : ifp_succ_n.fr.num < ifp_n.fr.num
begin obtain ⟨ifp_n', stream_nth_eq', ifp_n_fract_ne_zero, int_fract_pair.of_eq_ifp_succ_n⟩ : ∃ ifp_n', int_fract_pair.stream q n = some ifp_n' ∧ ifp_n'.fr ≠ 0 ∧ int_fract_pair.of ifp_n'.fr⁻¹ = ifp_succ_n, from succ_nth_stream_eq_some_iff.elim_left stream_succ_nth_eq, have : ifp_n = ifp_n', by injecti...
lemma
generalized_continued_fraction.int_fract_pair.stream_succ_nth_fr_num_lt_nth_fr_num_rat
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/terminates_iff_rat.lean
[ "algebra.continued_fractions.computation.approximations", "algebra.continued_fractions.computation.correctness_terminating", "data.rat.floor" ]
[]
Shows that the sequence of numerators of the fractional parts of the stream is strictly antitone.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
stream_nth_fr_num_le_fr_num_sub_n_rat : ∀ {ifp_n : int_fract_pair ℚ}, int_fract_pair.stream q n = some ifp_n → ifp_n.fr.num ≤ (int_fract_pair.of q).fr.num - n
begin induction n with n IH, case nat.zero { assume ifp_zero stream_zero_eq, have : int_fract_pair.of q = ifp_zero, by injection stream_zero_eq, simp [le_refl, this.symm] }, case nat.succ { assume ifp_succ_n stream_succ_nth_eq, suffices : ifp_succ_n.fr.num + 1 ≤ (int_fract_pair.of q).fr.num - n, b...
lemma
generalized_continued_fraction.int_fract_pair.stream_nth_fr_num_le_fr_num_sub_n_rat
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/terminates_iff_rat.lean
[ "algebra.continued_fractions.computation.approximations", "algebra.continued_fractions.computation.correctness_terminating", "data.rat.floor" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_nth_stream_eq_none_of_rat (q : ℚ) : ∃ (n : ℕ), int_fract_pair.stream q n = none
begin let fract_q_num := (int.fract q).num, let n := fract_q_num.nat_abs + 1, cases stream_nth_eq : (int_fract_pair.stream q n) with ifp, { use n, exact stream_nth_eq }, { -- arrive at a contradiction since the numerator decreased num + 1 times but every fractional -- value is nonnegative. have ifp_fr_n...
lemma
generalized_continued_fraction.int_fract_pair.exists_nth_stream_eq_none_of_rat
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/terminates_iff_rat.lean
[ "algebra.continued_fractions.computation.approximations", "algebra.continued_fractions.computation.correctness_terminating", "data.rat.floor" ]
[ "int.fract", "int.fract_nonneg", "num" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
terminates_of_rat (q : ℚ) : (of q).terminates
exists.elim (int_fract_pair.exists_nth_stream_eq_none_of_rat q) ( assume n stream_nth_eq_none, exists.intro n ( have int_fract_pair.stream q (n + 1) = none, from int_fract_pair.stream_is_seq q stream_nth_eq_none, (of_terminated_at_n_iff_succ_nth_int_fract_pair_stream_eq_none.elim_right this) ) )
theorem
generalized_continued_fraction.terminates_of_rat
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/terminates_iff_rat.lean
[ "algebra.continued_fractions.computation.approximations", "algebra.continued_fractions.computation.correctness_terminating", "data.rat.floor" ]
[]
The continued fraction of a rational number terminates.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
terminates_iff_rat (v : K) : (of v).terminates ↔ ∃ (q : ℚ), v = (q : K)
iff.intro ( assume terminates_v : (of v).terminates, show ∃ (q : ℚ), v = (q : K), from exists_rat_eq_of_terminates terminates_v ) ( assume exists_q_eq_v : ∃ (q : ℚ), v = (↑q : K), exists.elim exists_q_eq_v ( assume q, assume v_eq_q : v = ↑q, have (of q).terminates, from terminates_of_rat q, (of_termin...
theorem
generalized_continued_fraction.terminates_iff_rat
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/terminates_iff_rat.lean
[ "algebra.continued_fractions.computation.approximations", "algebra.continued_fractions.computation.correctness_terminating", "data.rat.floor" ]
[]
The continued fraction `generalized_continued_fraction.of v` terminates if and only if `v ∈ ℚ`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
stream_zero (v : K) : int_fract_pair.stream v 0 = some (int_fract_pair.of v)
rfl
lemma
generalized_continued_fraction.int_fract_pair.stream_zero
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
stream_eq_none_of_fr_eq_zero {ifp_n : int_fract_pair K} (stream_nth_eq : int_fract_pair.stream v n = some ifp_n) (nth_fr_eq_zero : ifp_n.fr = 0) : int_fract_pair.stream v (n + 1) = none
begin cases ifp_n with _ fr, change fr = 0 at nth_fr_eq_zero, simp [int_fract_pair.stream, stream_nth_eq, nth_fr_eq_zero] end
lemma
generalized_continued_fraction.int_fract_pair.stream_eq_none_of_fr_eq_zero
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
succ_nth_stream_eq_none_iff : int_fract_pair.stream v (n + 1) = none ↔ (int_fract_pair.stream v n = none ∨ ∃ ifp, int_fract_pair.stream v n = some ifp ∧ ifp.fr = 0)
begin rw [int_fract_pair.stream], cases int_fract_pair.stream v n; simp [imp_false] end
lemma
generalized_continued_fraction.int_fract_pair.succ_nth_stream_eq_none_iff
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[ "imp_false" ]
Gives a recurrence to compute the `n + 1`th value of the sequence of integer and fractional parts of a value in case of termination.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
succ_nth_stream_eq_some_iff {ifp_succ_n : int_fract_pair K} : int_fract_pair.stream v (n + 1) = some ifp_succ_n ↔ ∃ (ifp_n : int_fract_pair K), int_fract_pair.stream v n = some ifp_n ∧ ifp_n.fr ≠ 0 ∧ int_fract_pair.of ifp_n.fr⁻¹ = ifp_succ_n
by simp [int_fract_pair.stream, ite_eq_iff]
lemma
generalized_continued_fraction.int_fract_pair.succ_nth_stream_eq_some_iff
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[ "ite_eq_iff" ]
Gives a recurrence to compute the `n + 1`th value of the sequence of integer and fractional parts of a value in case of non-termination.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
stream_succ_of_some {p : int_fract_pair K} (h : int_fract_pair.stream v n = some p) (h' : p.fr ≠ 0) : int_fract_pair.stream v (n + 1) = some (int_fract_pair.of (p.fr)⁻¹)
succ_nth_stream_eq_some_iff.mpr ⟨p, h, h', rfl⟩
lemma
generalized_continued_fraction.int_fract_pair.stream_succ_of_some
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[]
An easier to use version of one direction of `generalized_continued_fraction.int_fract_pair.succ_nth_stream_eq_some_iff`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
stream_succ_of_int (a : ℤ) (n : ℕ) : int_fract_pair.stream (a : K) (n + 1) = none
begin induction n with n ih, { refine int_fract_pair.stream_eq_none_of_fr_eq_zero (int_fract_pair.stream_zero (a : K)) _, simp only [int_fract_pair.of, int.fract_int_cast], }, { exact int_fract_pair.succ_nth_stream_eq_none_iff.mpr (or.inl ih), } end
lemma
generalized_continued_fraction.int_fract_pair.stream_succ_of_int
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[ "ih", "int.fract_int_cast" ]
The stream of `int_fract_pair`s of an integer stops after the first term.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_succ_nth_stream_of_fr_zero {ifp_succ_n : int_fract_pair K} (stream_succ_nth_eq : int_fract_pair.stream v (n + 1) = some ifp_succ_n) (succ_nth_fr_eq_zero : ifp_succ_n.fr = 0) : ∃ ifp_n : int_fract_pair K, int_fract_pair.stream v n = some ifp_n ∧ ifp_n.fr⁻¹ = ⌊ifp_n.fr⁻¹⌋
begin -- get the witness from `succ_nth_stream_eq_some_iff` and prove that it has the additional -- properties rcases (succ_nth_stream_eq_some_iff.mp stream_succ_nth_eq) with ⟨ifp_n, seq_nth_eq, nth_fr_ne_zero, rfl⟩, refine ⟨ifp_n, seq_nth_eq, _⟩, simpa only [int_fract_pair.of, int.fract, sub_eq_zero] usi...
lemma
generalized_continued_fraction.int_fract_pair.exists_succ_nth_stream_of_fr_zero
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[ "int.fract" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
stream_succ (h : int.fract v ≠ 0) (n : ℕ) : int_fract_pair.stream v (n + 1) = int_fract_pair.stream (int.fract v)⁻¹ n
begin induction n with n ih, { have H : (int_fract_pair.of v).fr = int.fract v := rfl, rw [stream_zero, stream_succ_of_some (stream_zero v) (ne_of_eq_of_ne H h), H], }, { cases eq_or_ne (int_fract_pair.stream (int.fract v)⁻¹ n) none with hnone hsome, { rw hnone at ih, rw [succ_nth_stream_eq_none_iff...
lemma
generalized_continued_fraction.int_fract_pair.stream_succ
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[ "eq_or_ne", "ih", "int.fract" ]
A recurrence relation that expresses the `(n+1)`th term of the stream of `int_fract_pair`s of `v` for non-integer `v` in terms of the `n`th term of the stream associated to the inverse of the fractional part of `v`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
int_fract_pair.seq1_fst_eq_of : (int_fract_pair.seq1 v).fst = int_fract_pair.of v
rfl
lemma
generalized_continued_fraction.int_fract_pair.seq1_fst_eq_of
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[]
The head term of the sequence with head of `v` is just the integer part of `v`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_h_eq_int_fract_pair_seq1_fst_b : (of v).h = (int_fract_pair.seq1 v).fst.b
by { cases aux_seq_eq : (int_fract_pair.seq1 v), simp [of, aux_seq_eq] }
lemma
generalized_continued_fraction.of_h_eq_int_fract_pair_seq1_fst_b
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_h_eq_floor : (of v).h = ⌊v⌋
by simp [of_h_eq_int_fract_pair_seq1_fst_b, int_fract_pair.of]
lemma
generalized_continued_fraction.of_h_eq_floor
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[]
The head term of the gcf of `v` is `⌊v⌋`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
int_fract_pair.nth_seq1_eq_succ_nth_stream : (int_fract_pair.seq1 v).snd.nth n = (int_fract_pair.stream v) (n + 1)
rfl
lemma
generalized_continued_fraction.int_fract_pair.nth_seq1_eq_succ_nth_stream
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_terminated_at_iff_int_fract_pair_seq1_terminated_at : (of v).terminated_at n ↔ (int_fract_pair.seq1 v).snd.terminated_at n
option.map_eq_none
lemma
generalized_continued_fraction.of_terminated_at_iff_int_fract_pair_seq1_terminated_at
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[ "option.map_eq_none" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_terminated_at_n_iff_succ_nth_int_fract_pair_stream_eq_none : (of v).terminated_at n ↔ int_fract_pair.stream v (n + 1) = none
by rw [of_terminated_at_iff_int_fract_pair_seq1_terminated_at, stream.seq.terminated_at, int_fract_pair.nth_seq1_eq_succ_nth_stream]
lemma
generalized_continued_fraction.of_terminated_at_n_iff_succ_nth_int_fract_pair_stream_eq_none
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[ "stream.seq.terminated_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
int_fract_pair.exists_succ_nth_stream_of_gcf_of_nth_eq_some {gp_n : pair K} (s_nth_eq : (of v).s.nth n = some gp_n) : ∃ (ifp : int_fract_pair K), int_fract_pair.stream v (n + 1) = some ifp ∧ (ifp.b : K) = gp_n.b
begin obtain ⟨ifp, stream_succ_nth_eq, gp_n_eq⟩ : ∃ ifp, int_fract_pair.stream v (n + 1) = some ifp ∧ pair.mk 1 (ifp.b : K) = gp_n, by { unfold of int_fract_pair.seq1 at s_nth_eq, rwa [seq.map_tail, seq.nth_tail, seq.map_nth, option.map_eq_some'] at s_nth_eq }, cases gp_n_eq, injection gp_n_eq with ...
lemma
generalized_continued_fraction.int_fract_pair.exists_succ_nth_stream_of_gcf_of_nth_eq_some
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[ "option.map_eq_some'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nth_of_eq_some_of_succ_nth_int_fract_pair_stream {ifp_succ_n : int_fract_pair K} (stream_succ_nth_eq : int_fract_pair.stream v (n + 1) = some ifp_succ_n) : (of v).s.nth n = some ⟨1, ifp_succ_n.b⟩
begin unfold of int_fract_pair.seq1, rw [seq.map_tail, seq.nth_tail, seq.map_nth], simp [seq.nth, stream_succ_nth_eq] end
lemma
generalized_continued_fraction.nth_of_eq_some_of_succ_nth_int_fract_pair_stream
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[]
Shows how the entries of the sequence of the computed continued fraction can be obtained by the integer parts of the stream of integer and fractional parts.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nth_of_eq_some_of_nth_int_fract_pair_stream_fr_ne_zero {ifp_n : int_fract_pair K} (stream_nth_eq : int_fract_pair.stream v n = some ifp_n) (nth_fr_ne_zero : ifp_n.fr ≠ 0) : (of v).s.nth n = some ⟨1, (int_fract_pair.of ifp_n.fr⁻¹).b⟩
have int_fract_pair.stream v (n + 1) = some (int_fract_pair.of ifp_n.fr⁻¹), by { cases ifp_n, simp [int_fract_pair.stream, stream_nth_eq, nth_fr_ne_zero] }, nth_of_eq_some_of_succ_nth_int_fract_pair_stream this
lemma
generalized_continued_fraction.nth_of_eq_some_of_nth_int_fract_pair_stream_fr_ne_zero
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[]
Shows how the entries of the sequence of the computed continued fraction can be obtained by the fractional parts of the stream of integer and fractional parts.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_s_head_aux (v : K) : (of v).s.nth 0 = (int_fract_pair.stream v 1).bind (some ∘ λ p, {a := 1, b := p.b})
begin rw [of, int_fract_pair.seq1, of._match_1], simp only [seq.map_tail, seq.map, seq.tail, seq.head, seq.nth, stream.map], rw [← stream.nth_succ, stream.nth, option.map], end
lemma
generalized_continued_fraction.of_s_head_aux
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[ "stream.map", "stream.nth", "stream.nth_succ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_s_head (h : fract v ≠ 0) : (of v).s.head = some ⟨1, ⌊(fract v)⁻¹⌋⟩
begin change (of v).s.nth 0 = _, rw [of_s_head_aux, stream_succ_of_some (stream_zero v) h, option.bind], refl, end
lemma
generalized_continued_fraction.of_s_head
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[]
This gives the first pair of coefficients of the continued fraction of a non-integer `v`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_s_of_int (a : ℤ) : (of (a : K)).s = seq.nil
begin have h : ∀ n, (of (a : K)).s.nth n = none, { intro n, induction n with n ih, { rw [of_s_head_aux, stream_succ_of_int, option.bind], }, { exact (of (a : K)).s.prop ih, } }, exact seq.ext (λ n, (h n).trans (seq.nth_nil n).symm), end
lemma
generalized_continued_fraction.of_s_of_int
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[ "ih" ]
If `a` is an integer, then the coefficient sequence of its continued fraction is empty.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_s_succ (n : ℕ) : (of v).s.nth (n + 1) = (of (fract v)⁻¹).s.nth n
begin cases eq_or_ne (fract v) 0 with h h, { obtain ⟨a, rfl⟩ : ∃ a : ℤ, v = a := ⟨⌊v⌋, eq_of_sub_eq_zero h⟩, rw [fract_int_cast, inv_zero, of_s_of_int, ← cast_zero, of_s_of_int, seq.nth_nil, seq.nth_nil], }, cases eq_or_ne ((of (fract v)⁻¹).s.nth n) none with h₁ h₁, { rwa [h₁, ← terminated_at_iff_s...
lemma
generalized_continued_fraction.of_s_succ
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[ "eq_or_ne", "inv_zero" ]
Recurrence for the `generalized_continued_fraction.of` an element `v` of `K` in terms of that of the inverse of the fractional part of `v`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_s_tail : (of v).s.tail = (of (fract v)⁻¹).s
seq.ext $ λ n, seq.nth_tail (of v).s n ▸ of_s_succ v n
lemma
generalized_continued_fraction.of_s_tail
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[]
This expresses the tail of the coefficient sequence of the `generalized_continued_fraction.of` an element `v` of `K` as the coefficient sequence of that of the inverse of the fractional part of `v`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convergents'_of_int (a : ℤ) : (of (a : K)).convergents' n = a
begin induction n with n ih, { simp only [zeroth_convergent'_eq_h, of_h_eq_floor, floor_int_cast], }, { rw [convergents', of_h_eq_floor, floor_int_cast, add_right_eq_self], exact convergents'_aux_succ_none ((of_s_of_int K a).symm ▸ seq.nth_nil 0) _, } end
lemma
generalized_continued_fraction.convergents'_of_int
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[ "ih" ]
If `a` is an integer, then the `convergents'` of its continued fraction expansion are all equal to `a`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
convergents'_succ : (of v).convergents' (n + 1) = ⌊v⌋ + 1 / (of (fract v)⁻¹).convergents' n
begin cases eq_or_ne (fract v) 0 with h h, { obtain ⟨a, rfl⟩ : ∃ a : ℤ, v = a := ⟨⌊v⌋, eq_of_sub_eq_zero h⟩, rw [convergents'_of_int, fract_int_cast, inv_zero, ← cast_zero, convergents'_of_int, cast_zero, div_zero, add_zero, floor_int_cast], }, { rw [convergents', of_h_eq_floor, add_right_inj, converg...
lemma
generalized_continued_fraction.convergents'_succ
algebra.continued_fractions.computation
src/algebra/continued_fractions/computation/translations.lean
[ "algebra.continued_fractions.computation.basic", "algebra.continued_fractions.translations" ]
[ "div_zero", "eq_or_ne", "inv_zero" ]
The recurrence relation for the `convergents'` of the continued fraction expansion of an element `v` of `K` in terms of the convergents of the inverse of its fractional part.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
galgebra
(to_fun : R →+ A 0) (map_one : to_fun 1 = graded_monoid.ghas_one.one) (map_mul : ∀ r s, graded_monoid.mk _ (to_fun (r * s)) = ⟨_, graded_monoid.ghas_mul.mul (to_fun r) (to_fun s)⟩) (commutes : ∀ r x, graded_monoid.mk _ (to_fun r) * x = x * ⟨_, to_fun r⟩) (smul_def : ∀ r (x : graded_monoid A), graded_monoid.mk x.1 (r ...
class
direct_sum.galgebra
algebra.direct_sum
src/algebra/direct_sum/algebra.lean
[ "algebra.algebra.basic", "algebra.direct_sum.module", "algebra.direct_sum.ring" ]
[ "graded_monoid", "graded_monoid.mk", "map_mul", "map_one" ]
A graded version of `algebra`. An instance of `direct_sum.galgebra R A` endows `(⨁ i, A i)` with an `R`-algebra structure.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
algebra_map_apply (r : R) : algebra_map R (⨁ i, A i) r = direct_sum.of A 0 (galgebra.to_fun r)
rfl
lemma
direct_sum.algebra_map_apply
algebra.direct_sum
src/algebra/direct_sum/algebra.lean
[ "algebra.algebra.basic", "algebra.direct_sum.module", "algebra.direct_sum.ring" ]
[ "algebra_map", "algebra_map_apply", "direct_sum.of" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
algebra_map_to_add_monoid_hom : ↑(algebra_map R (⨁ i, A i)) = (direct_sum.of A 0).comp (galgebra.to_fun : R →+ A 0)
rfl
lemma
direct_sum.algebra_map_to_add_monoid_hom
algebra.direct_sum
src/algebra/direct_sum/algebra.lean
[ "algebra.algebra.basic", "algebra.direct_sum.module", "algebra.direct_sum.ring" ]
[ "algebra_map", "direct_sum.of" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_algebra (f : Π i, A i →ₗ[R] B) (hone : f _ (graded_monoid.ghas_one.one) = 1) (hmul : ∀ {i j} (ai : A i) (aj : A j), f _ (graded_monoid.ghas_mul.mul ai aj) = f _ ai * f _ aj) (hcommutes : ∀ r, (f 0) (galgebra.to_fun r) = (algebra_map R B) r) : (⨁ i, A i) →ₐ[R] B
{ to_fun := to_semiring (λ i, (f i).to_add_monoid_hom) hone @hmul, commutes' := λ r, (direct_sum.to_semiring_of _ _ _ _ _).trans (hcommutes r), .. to_semiring (λ i, (f i).to_add_monoid_hom) hone @hmul}
def
direct_sum.to_algebra
algebra.direct_sum
src/algebra/direct_sum/algebra.lean
[ "algebra.algebra.basic", "algebra.direct_sum.module", "algebra.direct_sum.ring" ]
[ "algebra_map", "direct_sum.to_semiring_of" ]
A family of `linear_map`s preserving `direct_sum.ghas_one.one` and `direct_sum.ghas_mul.mul` describes an `alg_hom` on `⨁ i, A i`. This is a stronger version of `direct_sum.to_semiring`. Of particular interest is the case when `A i` are bundled subojects, `f` is the family of coercions such as `submodule.subtype (A i)...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
alg_hom_ext' ⦃f g : (⨁ i, A i) →ₐ[R] B⦄ (h : ∀ i, f.to_linear_map.comp (lof _ _ A i) = g.to_linear_map.comp (lof _ _ A i)) : f = g
alg_hom.to_linear_map_injective $ direct_sum.linear_map_ext _ h
lemma
direct_sum.alg_hom_ext'
algebra.direct_sum
src/algebra/direct_sum/algebra.lean
[ "algebra.algebra.basic", "algebra.direct_sum.module", "algebra.direct_sum.ring" ]
[ "alg_hom.to_linear_map_injective", "direct_sum.linear_map_ext" ]
Two `alg_hom`s out of a direct sum are equal if they agree on the generators. See note [partially-applied ext lemmas].
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
alg_hom_ext ⦃f g : (⨁ i, A i) →ₐ[R] B⦄ (h : ∀ i x, f (of A i x) = g (of A i x)) : f = g
alg_hom_ext' R A $ λ i, linear_map.ext $ h i
lemma
direct_sum.alg_hom_ext
algebra.direct_sum
src/algebra/direct_sum/algebra.lean
[ "algebra.algebra.basic", "algebra.direct_sum.module", "algebra.direct_sum.ring" ]
[ "linear_map.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
algebra.direct_sum_galgebra {R A : Type*} [decidable_eq ι] [add_monoid ι] [comm_semiring R] [semiring A] [algebra R A] : direct_sum.galgebra R (λ i : ι, A)
{ to_fun := (algebra_map R A).to_add_monoid_hom, map_one := (algebra_map R A).map_one, map_mul := λ a b, sigma.ext (zero_add _).symm (heq_of_eq $ (algebra_map R A).map_mul a b), commutes := λ r ⟨ai, a⟩, sigma.ext ((zero_add _).trans (add_zero _).symm) (heq_of_eq $ algebra.commu...
instance
algebra.direct_sum_galgebra
algebra.direct_sum
src/algebra/direct_sum/algebra.lean
[ "algebra.algebra.basic", "algebra.direct_sum.module", "algebra.direct_sum.ring" ]
[ "add_monoid", "algebra", "algebra.commutes", "algebra.smul_def", "algebra_map", "comm_semiring", "direct_sum.galgebra", "map_mul", "map_one", "semiring", "sigma.ext" ]
A direct sum of copies of a `algebra` inherits the algebra structure.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
direct_sum [Π i, add_comm_monoid (β i)] : Type*
Π₀ i, β i
def
direct_sum
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "add_comm_monoid" ]
`direct_sum β` is the direct sum of a family of additive commutative monoids `β i`. Note: `open_locale direct_sum` will enable the notation `⨁ i, β i` for `direct_sum β`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sub_apply (g₁ g₂ : ⨁ i, β i) (i : ι) : (g₁ - g₂) i = g₁ i - g₂ i
rfl
lemma
direct_sum.sub_apply
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
zero_apply (i : ι) : (0 : ⨁ i, β i) i = 0
rfl
lemma
direct_sum.zero_apply
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_apply (g₁ g₂ : ⨁ i, β i) (i : ι) : (g₁ + g₂) i = g₁ i + g₂ i
rfl
lemma
direct_sum.add_apply
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk (s : finset ι) : (Π i : (↑s : set ι), β i.1) →+ ⨁ i, β i
{ to_fun := dfinsupp.mk s, map_add' := λ _ _, dfinsupp.mk_add, map_zero' := dfinsupp.mk_zero, }
def
direct_sum.mk
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.mk", "dfinsupp.mk_add", "dfinsupp.mk_zero", "finset" ]
`mk β s x` is the element of `⨁ i, β i` that is zero outside `s` and has coefficient `x i` for `i` in `s`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of (i : ι) : β i →+ ⨁ i, β i
dfinsupp.single_add_hom β i
def
direct_sum.of
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.single_add_hom" ]
`of i` is the natural inclusion map from `β i` to `⨁ i, β i`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_eq_same (i : ι) (x : β i) : (of _ i x) i = x
dfinsupp.single_eq_same
lemma
direct_sum.of_eq_same
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.single_eq_same" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_eq_of_ne (i j : ι) (x : β i) (h : i ≠ j) : (of _ i x) j = 0
dfinsupp.single_eq_of_ne h
lemma
direct_sum.of_eq_of_ne
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.single_eq_of_ne" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
support_zero [Π (i : ι) (x : β i), decidable (x ≠ 0)] : (0 : ⨁ i, β i).support = ∅
dfinsupp.support_zero
lemma
direct_sum.support_zero
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.support_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
support_of [Π (i : ι) (x : β i), decidable (x ≠ 0)] (i : ι) (x : β i) (h : x ≠ 0) : (of _ i x).support = {i}
dfinsupp.support_single_ne_zero h
lemma
direct_sum.support_of
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.support_single_ne_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
support_of_subset [Π (i : ι) (x : β i), decidable (x ≠ 0)] {i : ι} {b : β i} : (of _ i b).support ⊆ {i}
dfinsupp.support_single_subset
lemma
direct_sum.support_of_subset
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.support_single_subset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sum_support_of [Π (i : ι) (x : β i), decidable (x ≠ 0)] (x : ⨁ i, β i) : ∑ i in x.support, of β i (x i) = x
dfinsupp.sum_single
lemma
direct_sum.sum_support_of
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.sum_single" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_injective (s : finset ι) : function.injective (mk β s)
dfinsupp.mk_injective s
theorem
direct_sum.mk_injective
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.mk_injective", "finset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_injective (i : ι) : function.injective (of β i)
dfinsupp.single_injective
theorem
direct_sum.of_injective
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.single_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
induction_on {C : (⨁ i, β i) → Prop} (x : ⨁ i, β i) (H_zero : C 0) (H_basic : ∀ (i : ι) (x : β i), C (of β i x)) (H_plus : ∀ x y, C x → C y → C (x + y)) : C x
begin apply dfinsupp.induction x H_zero, intros i b f h1 h2 ih, solve_by_elim end
theorem
direct_sum.induction_on
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.induction", "ih" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_hom_ext {γ : Type*} [add_monoid γ] ⦃f g : (⨁ i, β i) →+ γ⦄ (H : ∀ (i : ι) (y : β i), f (of _ i y) = g (of _ i y)) : f = g
dfinsupp.add_hom_ext H
lemma
direct_sum.add_hom_ext
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "add_monoid", "dfinsupp.add_hom_ext" ]
If two additive homomorphisms from `⨁ i, β i` are equal on each `of β i y`, then they are equal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_hom_ext' {γ : Type*} [add_monoid γ] ⦃f g : (⨁ i, β i) →+ γ⦄ (H : ∀ (i : ι), f.comp (of _ i) = g.comp (of _ i)) : f = g
add_hom_ext $ λ i, add_monoid_hom.congr_fun $ H i
lemma
direct_sum.add_hom_ext'
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "add_monoid" ]
If two additive homomorphisms from `⨁ i, β i` are equal on each `of β i y`, then they are equal. See note [partially-applied ext lemmas].
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_add_monoid : (⨁ i, β i) →+ γ
(dfinsupp.lift_add_hom φ)
def
direct_sum.to_add_monoid
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.lift_add_hom" ]
`to_add_monoid φ` is the natural homomorphism from `⨁ i, β i` to `γ` induced by a family `φ` of homomorphisms `β i → γ`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_add_monoid_of (i) (x : β i) : to_add_monoid φ (of β i x) = φ i x
dfinsupp.lift_add_hom_apply_single φ i x
lemma
direct_sum.to_add_monoid_of
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.lift_add_hom_apply_single" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_add_monoid.unique (f : ⨁ i, β i) : ψ f = to_add_monoid (λ i, ψ.comp (of β i)) f
by {congr, ext, simp [to_add_monoid, of]}
theorem
direct_sum.to_add_monoid.unique
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
from_add_monoid : (⨁ i, γ →+ β i) →+ (γ →+ ⨁ i, β i)
to_add_monoid $ λ i, add_monoid_hom.comp_hom (of β i)
def
direct_sum.from_add_monoid
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[]
`from_add_monoid φ` is the natural homomorphism from `γ` to `⨁ i, β i` induced by a family `φ` of homomorphisms `γ → β i`. Note that this is not an isomorphism. Not every homomorphism `γ →+ ⨁ i, β i` arises in this way.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
from_add_monoid_of (i : ι) (f : γ →+ β i) : from_add_monoid (of _ i f) = (of _ i).comp f
by { rw [from_add_monoid, to_add_monoid_of], refl }
lemma
direct_sum.from_add_monoid_of
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
from_add_monoid_of_apply (i : ι) (f : γ →+ β i) (x : γ) : from_add_monoid (of _ i f) x = of _ i (f x)
by rw [from_add_monoid_of, add_monoid_hom.coe_comp]
lemma
direct_sum.from_add_monoid_of_apply
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set_to_set (S T : set ι) (H : S ⊆ T) : (⨁ (i : S), β i) →+ (⨁ (i : T), β i)
to_add_monoid $ λ i, of (λ (i : subtype T), β i) ⟨↑i, H i.prop⟩
def
direct_sum.set_to_set
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unique [∀ i, subsingleton (β i)] : unique (⨁ i, β i)
dfinsupp.unique
instance
direct_sum.unique
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.unique", "unique" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unique_of_is_empty [is_empty ι] : unique (⨁ i, β i)
dfinsupp.unique_of_is_empty
instance
direct_sum.unique_of_is_empty
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.unique_of_is_empty", "is_empty", "unique" ]
A direct sum over an empty type is trivial.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
id (M : Type v) (ι : Type* := punit) [add_comm_monoid M] [unique ι] : (⨁ (_ : ι), M) ≃+ M
{ to_fun := direct_sum.to_add_monoid (λ _, add_monoid_hom.id M), inv_fun := of (λ _, M) default, left_inv := λ x, direct_sum.induction_on x (by rw [add_monoid_hom.map_zero, add_monoid_hom.map_zero]) (λ p x, by rw [unique.default_eq p, to_add_monoid_of]; refl) (λ x y ihx ihy, by rw [add_monoid_hom.map_ad...
def
direct_sum.id
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "add_comm_monoid", "direct_sum.induction_on", "direct_sum.to_add_monoid", "inv_fun", "unique", "unique.default_eq" ]
The natural equivalence between `⨁ _ : ι, M` and `M` when `unique ι`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equiv_congr_left (h : ι ≃ κ) : (⨁ i, β i) ≃+ ⨁ k, β (h.symm k)
{ map_add' := dfinsupp.comap_domain'_add _ _, ..dfinsupp.equiv_congr_left h }
def
direct_sum.equiv_congr_left
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.comap_domain'_add", "dfinsupp.equiv_congr_left" ]
Reindexing terms of a direct sum.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equiv_congr_left_apply (h : ι ≃ κ) (f : ⨁ i, β i) (k : κ) : equiv_congr_left h f k = f (h.symm k)
dfinsupp.comap_domain'_apply _ _ _ _
lemma
direct_sum.equiv_congr_left_apply
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.comap_domain'_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_equiv_prod_direct_sum : (⨁ i, α i) ≃+ α none × ⨁ i, α (some i)
{ map_add' := dfinsupp.equiv_prod_dfinsupp_add, ..dfinsupp.equiv_prod_dfinsupp }
def
direct_sum.add_equiv_prod_direct_sum
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.equiv_prod_dfinsupp", "dfinsupp.equiv_prod_dfinsupp_add" ]
Isomorphism obtained by separating the term of index `none` of a direct sum over `option ι`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma_curry : (⨁ (i : Σ i, _), δ i.1 i.2) →+ ⨁ i j, δ i j
{ to_fun := @dfinsupp.sigma_curry _ _ δ _, map_zero' := dfinsupp.sigma_curry_zero, map_add' := λ f g, @dfinsupp.sigma_curry_add _ _ δ _ f g }
def
direct_sum.sigma_curry
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.sigma_curry", "dfinsupp.sigma_curry_add", "dfinsupp.sigma_curry_zero" ]
The natural map between `⨁ (i : Σ i, α i), δ i.1 i.2` and `⨁ i (j : α i), δ i j`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma_curry_apply (f : ⨁ (i : Σ i, _), δ i.1 i.2) (i : ι) (j : α i) : sigma_curry f i j = f ⟨i, j⟩
@dfinsupp.sigma_curry_apply _ _ δ _ f i j
lemma
direct_sum.sigma_curry_apply
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.sigma_curry_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma_uncurry [Π i, decidable_eq (α i)] [Π i j, decidable_eq (δ i j)] : (⨁ i j, δ i j) →+ ⨁ (i : Σ i, _), δ i.1 i.2
{ to_fun := dfinsupp.sigma_uncurry, map_zero' := dfinsupp.sigma_uncurry_zero, map_add' := dfinsupp.sigma_uncurry_add }
def
direct_sum.sigma_uncurry
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.sigma_uncurry", "dfinsupp.sigma_uncurry_add", "dfinsupp.sigma_uncurry_zero" ]
The natural map between `⨁ i (j : α i), δ i j` and `Π₀ (i : Σ i, α i), δ i.1 i.2`, inverse of `curry`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma_uncurry_apply [Π i, decidable_eq (α i)] [Π i j, decidable_eq (δ i j)] (f : ⨁ i j, δ i j) (i : ι) (j : α i) : sigma_uncurry f ⟨i, j⟩ = f i j
dfinsupp.sigma_uncurry_apply f i j
lemma
direct_sum.sigma_uncurry_apply
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.sigma_uncurry_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma_curry_equiv [Π i, decidable_eq (α i)] [Π i j, decidable_eq (δ i j)] : (⨁ (i : Σ i, _), δ i.1 i.2) ≃+ ⨁ i j, δ i j
{ ..sigma_curry, ..dfinsupp.sigma_curry_equiv }
def
direct_sum.sigma_curry_equiv
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "dfinsupp.sigma_curry_equiv" ]
The natural map between `⨁ (i : Σ i, α i), δ i.1 i.2` and `⨁ i (j : α i), δ i j`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_add_monoid_hom {M S : Type*} [decidable_eq ι] [add_comm_monoid M] [set_like S M] [add_submonoid_class S M] (A : ι → S) : (⨁ i, A i) →+ M
to_add_monoid (λ i, add_submonoid_class.subtype (A i))
def
direct_sum.coe_add_monoid_hom
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "add_comm_monoid", "add_submonoid_class", "set_like" ]
The canonical embedding from `⨁ i, A i` to `M` where `A` is a collection of `add_submonoid M` indexed by `ι`. When `S = submodule _ M`, this is available as a `linear_map`, `direct_sum.coe_linear_map`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_add_monoid_hom_of {M S : Type*} [decidable_eq ι] [add_comm_monoid M] [set_like S M] [add_submonoid_class S M] (A : ι → S) (i : ι) (x : A i) : direct_sum.coe_add_monoid_hom A (of (λ i, A i) i x) = x
to_add_monoid_of _ _ _
lemma
direct_sum.coe_add_monoid_hom_of
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "add_comm_monoid", "add_submonoid_class", "direct_sum.coe_add_monoid_hom", "set_like" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_of_apply {M S : Type*} [decidable_eq ι] [add_comm_monoid M] [set_like S M] [add_submonoid_class S M] {A : ι → S} (i j : ι) (x : A i) : (of _ i x j : M) = if i = j then x else 0
begin obtain rfl | h := decidable.eq_or_ne i j, { rw [direct_sum.of_eq_same, if_pos rfl], }, { rw [direct_sum.of_eq_of_ne _ _ _ _ h, if_neg h, zero_mem_class.coe_zero], }, end
lemma
direct_sum.coe_of_apply
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "add_comm_monoid", "add_submonoid_class", "decidable.eq_or_ne", "direct_sum.of_eq_of_ne", "direct_sum.of_eq_same", "set_like" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_internal {M S : Type*} [decidable_eq ι] [add_comm_monoid M] [set_like S M] [add_submonoid_class S M] (A : ι → S) : Prop
function.bijective (direct_sum.coe_add_monoid_hom A)
def
direct_sum.is_internal
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "add_comm_monoid", "add_submonoid_class", "direct_sum.coe_add_monoid_hom", "set_like" ]
The `direct_sum` formed by a collection of additive submonoids (or subgroups, or submodules) of `M` is said to be internal if the canonical map `(⨁ i, A i) →+ M` is bijective. For the alternate statement in terms of independence and spanning, see `direct_sum.subgroup_is_internal_iff_independent_and_supr_eq_top` and `d...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_internal.add_submonoid_supr_eq_top {M : Type*} [decidable_eq ι] [add_comm_monoid M] (A : ι → add_submonoid M) (h : is_internal A) : supr A = ⊤
begin rw [add_submonoid.supr_eq_mrange_dfinsupp_sum_add_hom, add_monoid_hom.mrange_top_iff_surjective], exact function.bijective.surjective h, end
lemma
direct_sum.is_internal.add_submonoid_supr_eq_top
algebra.direct_sum
src/algebra/direct_sum/basic.lean
[ "data.dfinsupp.basic", "group_theory.submonoid.operations" ]
[ "add_comm_monoid", "add_submonoid", "add_submonoid.supr_eq_mrange_dfinsupp_sum_add_hom", "function.bijective.surjective", "supr" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decomposition
(decompose' : M → ⨁ i, ℳ i) (left_inv : function.left_inverse (direct_sum.coe_add_monoid_hom ℳ) decompose' ) (right_inv : function.right_inverse (direct_sum.coe_add_monoid_hom ℳ) decompose')
class
direct_sum.decomposition
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[ "direct_sum.coe_add_monoid_hom" ]
A decomposition is an equivalence between an additive monoid `M` and a direct sum of additive submonoids `ℳ i` of that `M`, such that the "recomposition" is canonical. This definition also works for additive groups and modules. This is a version of `direct_sum.is_internal` which comes with a constructive inverse to th...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decomposition.is_internal : direct_sum.is_internal ℳ
⟨decomposition.right_inv.injective, decomposition.left_inv.surjective⟩
lemma
direct_sum.decomposition.is_internal
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[ "direct_sum.is_internal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose : M ≃ ⨁ i, ℳ i
{ to_fun := decomposition.decompose', inv_fun := direct_sum.coe_add_monoid_hom ℳ, left_inv := decomposition.left_inv, right_inv := decomposition.right_inv }
def
direct_sum.decompose
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[ "direct_sum.coe_add_monoid_hom", "inv_fun" ]
If `M` is graded by `ι` with degree `i` component `ℳ i`, then it is isomorphic as to a direct sum of components. This is the canonical spelling of the `decompose'` field.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decomposition.induction_on {p : M → Prop} (h_zero : p 0) (h_homogeneous : ∀ {i} (m : ℳ i), p (m : M)) (h_add : ∀ (m m' : M), p m → p m' → p (m + m')) : ∀ m, p m
begin let ℳ' : ι → add_submonoid M := λ i, (⟨ℳ i, λ _ _, add_mem_class.add_mem, zero_mem_class.zero_mem _⟩ : add_submonoid M), haveI t : direct_sum.decomposition ℳ' := { decompose' := direct_sum.decompose ℳ, left_inv := λ _, (decompose ℳ).left_inv _, right_inv := λ _, (decompose ℳ).right_inv _, }, h...
lemma
direct_sum.decomposition.induction_on
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[ "add_submonoid", "direct_sum.decompose", "direct_sum.decomposition", "direct_sum.is_internal.add_submonoid_supr_eq_top", "supr" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decomposition.decompose'_eq : decomposition.decompose' = decompose ℳ
rfl
lemma
direct_sum.decomposition.decompose'_eq
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_symm_of {i : ι} (x : ℳ i) : (decompose ℳ).symm (direct_sum.of _ i x) = x
direct_sum.coe_add_monoid_hom_of ℳ _ _
lemma
direct_sum.decompose_symm_of
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[ "direct_sum.coe_add_monoid_hom_of", "direct_sum.of" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_coe {i : ι} (x : ℳ i) : decompose ℳ (x : M) = direct_sum.of _ i x
by rw [←decompose_symm_of, equiv.apply_symm_apply]
lemma
direct_sum.decompose_coe
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[ "direct_sum.of", "equiv.apply_symm_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_of_mem {x : M} {i : ι} (hx : x ∈ ℳ i) : decompose ℳ x = direct_sum.of (λ i, ℳ i) i ⟨x, hx⟩
decompose_coe _ ⟨x, hx⟩
lemma
direct_sum.decompose_of_mem
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[ "direct_sum.of" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_of_mem_same {x : M} {i : ι} (hx : x ∈ ℳ i) : (decompose ℳ x i : M) = x
by rw [decompose_of_mem _ hx, direct_sum.of_eq_same, subtype.coe_mk]
lemma
direct_sum.decompose_of_mem_same
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[ "direct_sum.of_eq_same", "subtype.coe_mk" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_of_mem_ne {x : M} {i j : ι} (hx : x ∈ ℳ i) (hij : i ≠ j): (decompose ℳ x j : M) = 0
by rw [decompose_of_mem _ hx, direct_sum.of_eq_of_ne _ _ _ _ hij, zero_mem_class.coe_zero]
lemma
direct_sum.decompose_of_mem_ne
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[ "direct_sum.of_eq_of_ne" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_add_equiv : M ≃+ ⨁ i, ℳ i
add_equiv.symm { map_add' := map_add (direct_sum.coe_add_monoid_hom ℳ), ..(decompose ℳ).symm }
def
direct_sum.decompose_add_equiv
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[ "direct_sum.coe_add_monoid_hom" ]
If `M` is graded by `ι` with degree `i` component `ℳ i`, then it is isomorphic as an additive monoid to a direct sum of components.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_zero : decompose ℳ (0 : M) = 0
map_zero (decompose_add_equiv ℳ)
lemma
direct_sum.decompose_zero
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_symm_zero : (decompose ℳ).symm 0 = (0 : M)
map_zero (decompose_add_equiv ℳ).symm
lemma
direct_sum.decompose_symm_zero
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_add (x y : M) : decompose ℳ (x + y) = decompose ℳ x + decompose ℳ y
map_add (decompose_add_equiv ℳ) x y
lemma
direct_sum.decompose_add
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_symm_add (x y : ⨁ i, ℳ i) : (decompose ℳ).symm (x + y) = (decompose ℳ).symm x + (decompose ℳ).symm y
map_add (decompose_add_equiv ℳ).symm x y
lemma
direct_sum.decompose_symm_add
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_sum {ι'} (s : finset ι') (f : ι' → M) : decompose ℳ (∑ i in s, f i) = ∑ i in s, decompose ℳ (f i)
map_sum (decompose_add_equiv ℳ) f s
lemma
direct_sum.decompose_sum
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[ "finset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83