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decompose_symm_sum {ι'} (s : finset ι') (f : ι' → ⨁ i, ℳ i) : (decompose ℳ).symm (∑ i in s, f i) = ∑ i in s, (decompose ℳ).symm (f i)
map_sum (decompose_add_equiv ℳ).symm f s
lemma
direct_sum.decompose_symm_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
sum_support_decompose [Π i (x : ℳ i), decidable (x ≠ 0)] (r : M) : ∑ i in (decompose ℳ r).support, (decompose ℳ r i : M) = r
begin conv_rhs { rw [←(decompose ℳ).symm_apply_apply r, ←sum_support_of (λ i, (ℳ i)) (decompose ℳ r)] }, rw [decompose_symm_sum], simp_rw decompose_symm_of, end
lemma
direct_sum.sum_support_decompose
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_comm_group_set_like [add_comm_group M] [set_like σ M] [add_subgroup_class σ M] (ℳ : ι → σ) : add_comm_group (⨁ i, ℳ i)
by apply_instance
instance
direct_sum.add_comm_group_set_like
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[ "add_comm_group", "add_subgroup_class", "set_like" ]
The `-` in the statements below doesn't resolve without this line. This seems to a be a problem of synthesized vs inferred typeclasses disagreeing. If we replace the statement of `decompose_neg` with `@eq (⨁ i, ℳ i) (decompose ℳ (-x)) (-decompose ℳ x)` instead of `decompose ℳ (-x) = -decompose ℳ x`, which forces the t...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_neg (x : M) : decompose ℳ (-x) = -decompose ℳ x
map_neg (decompose_add_equiv ℳ) x
lemma
direct_sum.decompose_neg
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_neg (x : ⨁ i, ℳ i) : (decompose ℳ).symm (-x) = -(decompose ℳ).symm x
map_neg (decompose_add_equiv ℳ).symm x
lemma
direct_sum.decompose_symm_neg
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_sub (x y : M) : decompose ℳ (x - y) = decompose ℳ x - decompose ℳ y
map_sub (decompose_add_equiv ℳ) x y
lemma
direct_sum.decompose_sub
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_sub (x y : ⨁ i, ℳ i) : (decompose ℳ).symm (x - y) = (decompose ℳ).symm x - (decompose ℳ).symm y
map_sub (decompose_add_equiv ℳ).symm x y
lemma
direct_sum.decompose_symm_sub
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_linear_equiv : M ≃ₗ[R] ⨁ i, ℳ i
linear_equiv.symm { map_smul' := map_smul (direct_sum.coe_linear_map ℳ), ..(decompose_add_equiv ℳ).symm }
def
direct_sum.decompose_linear_equiv
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[ "direct_sum.coe_linear_map", "linear_equiv.symm" ]
If `M` is graded by `ι` with degree `i` component `ℳ i`, then it is isomorphic as a module to a direct sum of components.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_smul (r : R) (x : M) : decompose ℳ (r • x) = r • decompose ℳ x
map_smul (decompose_linear_equiv ℳ) r x
lemma
direct_sum.decompose_smul
algebra.direct_sum
src/algebra/direct_sum/decomposition.lean
[ "algebra.direct_sum.module", "algebra.module.submodule.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finsupp_lequiv_direct_sum : (ι →₀ M) ≃ₗ[R] ⨁ i : ι, M
by haveI : Π m : M, decidable (m ≠ 0) := classical.dec_pred _; exact finsupp_lequiv_dfinsupp R
def
finsupp_lequiv_direct_sum
algebra.direct_sum
src/algebra/direct_sum/finsupp.lean
[ "algebra.direct_sum.module", "data.finsupp.to_dfinsupp" ]
[ "classical.dec_pred", "finsupp_lequiv_dfinsupp" ]
The finitely supported functions `ι →₀ M` are in linear equivalence with the direct sum of copies of M indexed by ι.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finsupp_lequiv_direct_sum_single (i : ι) (m : M) : finsupp_lequiv_direct_sum R M ι (finsupp.single i m) = direct_sum.lof R ι _ i m
finsupp.to_dfinsupp_single i m
theorem
finsupp_lequiv_direct_sum_single
algebra.direct_sum
src/algebra/direct_sum/finsupp.lean
[ "algebra.direct_sum.module", "data.finsupp.to_dfinsupp" ]
[ "direct_sum.lof", "finsupp.single", "finsupp.to_dfinsupp_single", "finsupp_lequiv_direct_sum" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finsupp_lequiv_direct_sum_symm_lof (i : ι) (m : M) : (finsupp_lequiv_direct_sum R M ι).symm (direct_sum.lof R ι _ i m) = finsupp.single i m
begin letI : Π m : M, decidable (m ≠ 0) := classical.dec_pred _, exact (dfinsupp.to_finsupp_single i m), end
theorem
finsupp_lequiv_direct_sum_symm_lof
algebra.direct_sum
src/algebra/direct_sum/finsupp.lean
[ "algebra.direct_sum.module", "data.finsupp.to_dfinsupp" ]
[ "classical.dec_pred", "dfinsupp.to_finsupp_single", "direct_sum.lof", "finsupp.single", "finsupp_lequiv_direct_sum" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_comm_monoid.of_submonoid_on_semiring [semiring R] [set_like σ R] [add_submonoid_class σ R] (A : ι → σ) : ∀ i, add_comm_monoid (A i)
λ i, by apply_instance
instance
add_comm_monoid.of_submonoid_on_semiring
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_comm_monoid", "add_submonoid_class", "semiring", "set_like" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_comm_group.of_subgroup_on_ring [ring R] [set_like σ R] [add_subgroup_class σ R] (A : ι → σ) : ∀ i, add_comm_group (A i)
λ i, by apply_instance
instance
add_comm_group.of_subgroup_on_ring
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_comm_group", "add_subgroup_class", "ring", "set_like" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set_like.algebra_map_mem_graded [has_zero ι] [comm_semiring S] [semiring R] [algebra S R] (A : ι → submodule S R) [set_like.has_graded_one A] (s : S) : algebra_map S R s ∈ A 0
begin rw algebra.algebra_map_eq_smul_one, exact ((A 0).smul_mem s $ set_like.one_mem_graded _), end
lemma
set_like.algebra_map_mem_graded
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "algebra", "algebra.algebra_map_eq_smul_one", "algebra_map", "comm_semiring", "semiring", "set_like.has_graded_one", "set_like.one_mem_graded", "submodule" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set_like.nat_cast_mem_graded [has_zero ι] [add_monoid_with_one R] [set_like σ R] [add_submonoid_class σ R] (A : ι → σ) [set_like.has_graded_one A] (n : ℕ) : (n : R) ∈ A 0
begin induction n, { rw nat.cast_zero, exact zero_mem (A 0), }, { rw nat.cast_succ, exact add_mem n_ih (set_like.one_mem_graded _), }, end
lemma
set_like.nat_cast_mem_graded
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_monoid_with_one", "add_submonoid_class", "nat.cast_succ", "nat.cast_zero", "set_like", "set_like.has_graded_one", "set_like.one_mem_graded" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set_like.int_cast_mem_graded [has_zero ι] [add_group_with_one R] [set_like σ R] [add_subgroup_class σ R] (A : ι → σ) [set_like.has_graded_one A] (z : ℤ) : (z : R) ∈ A 0
begin induction z, { rw int.cast_of_nat, exact set_like.nat_cast_mem_graded _ _, }, { rw int.cast_neg_succ_of_nat, exact neg_mem (set_like.nat_cast_mem_graded _ _), }, end
lemma
set_like.int_cast_mem_graded
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_group_with_one", "add_subgroup_class", "int.cast_neg_succ_of_nat", "int.cast_of_nat", "set_like", "set_like.has_graded_one", "set_like.nat_cast_mem_graded" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
gnon_unital_non_assoc_semiring [has_add ι] [non_unital_non_assoc_semiring R] [set_like σ R] [add_submonoid_class σ R] (A : ι → σ) [set_like.has_graded_mul A] : direct_sum.gnon_unital_non_assoc_semiring (λ i, A i)
{ mul_zero := λ i j _, subtype.ext (mul_zero _), zero_mul := λ i j _, subtype.ext (zero_mul _), mul_add := λ i j _ _ _, subtype.ext (mul_add _ _ _), add_mul := λ i j _ _ _, subtype.ext (add_mul _ _ _), ..set_like.ghas_mul A }
instance
set_like.gnon_unital_non_assoc_semiring
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_submonoid_class", "direct_sum.gnon_unital_non_assoc_semiring", "mul_zero", "non_unital_non_assoc_semiring", "set_like", "set_like.ghas_mul", "set_like.has_graded_mul", "subtype.ext", "zero_mul" ]
Build a `gnon_unital_non_assoc_semiring` instance for a collection of additive submonoids.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
gsemiring [add_monoid ι] [semiring R] [set_like σ R] [add_submonoid_class σ R] (A : ι → σ) [set_like.graded_monoid A] : direct_sum.gsemiring (λ i, A i)
{ mul_zero := λ i j _, subtype.ext (mul_zero _), zero_mul := λ i j _, subtype.ext (zero_mul _), mul_add := λ i j _ _ _, subtype.ext (mul_add _ _ _), add_mul := λ i j _ _ _, subtype.ext (add_mul _ _ _), nat_cast := λ n, ⟨n, set_like.nat_cast_mem_graded _ _⟩, nat_cast_zero := subtype.ext nat.cast_zero, nat_ca...
instance
set_like.gsemiring
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_monoid", "add_submonoid_class", "direct_sum.gsemiring", "mul_zero", "nat.cast_succ", "nat.cast_zero", "semiring", "set_like", "set_like.gmonoid", "set_like.graded_monoid", "set_like.nat_cast_mem_graded", "subtype.ext", "zero_mul" ]
Build a `gsemiring` instance for a collection of additive submonoids.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
gcomm_semiring [add_comm_monoid ι] [comm_semiring R] [set_like σ R] [add_submonoid_class σ R] (A : ι → σ) [set_like.graded_monoid A] : direct_sum.gcomm_semiring (λ i, A i)
{ ..set_like.gcomm_monoid A, ..set_like.gsemiring A, }
instance
set_like.gcomm_semiring
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_comm_monoid", "add_submonoid_class", "comm_semiring", "direct_sum.gcomm_semiring", "set_like", "set_like.gcomm_monoid", "set_like.graded_monoid", "set_like.gsemiring" ]
Build a `gcomm_semiring` instance for a collection of additive submonoids.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
gring [add_monoid ι] [ring R] [set_like σ R] [add_subgroup_class σ R] (A : ι → σ) [set_like.graded_monoid A] : direct_sum.gring (λ i, A i)
{ int_cast := λ z, ⟨z, set_like.int_cast_mem_graded _ _⟩, int_cast_of_nat := λ n, subtype.ext $ int.cast_of_nat _, int_cast_neg_succ_of_nat := λ n, subtype.ext $ int.cast_neg_succ_of_nat n, ..set_like.gsemiring A }
instance
set_like.gring
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_monoid", "add_subgroup_class", "direct_sum.gring", "int.cast_neg_succ_of_nat", "int.cast_of_nat", "ring", "set_like", "set_like.graded_monoid", "set_like.gsemiring", "set_like.int_cast_mem_graded", "subtype.ext" ]
Build a `gring` instance for a collection of additive subgroups.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
gcomm_ring [add_comm_monoid ι] [comm_ring R] [set_like σ R] [add_subgroup_class σ R] (A : ι → σ) [set_like.graded_monoid A] : direct_sum.gcomm_ring (λ i, A i)
{ ..set_like.gcomm_monoid A, ..set_like.gring A, }
instance
set_like.gcomm_ring
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_comm_monoid", "add_subgroup_class", "comm_ring", "direct_sum.gcomm_ring", "set_like", "set_like.gcomm_monoid", "set_like.graded_monoid", "set_like.gring" ]
Build a `gcomm_semiring` instance for a collection of additive submonoids.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_ring_hom [add_monoid ι] [set_like.graded_monoid A] : (⨁ i, A i) →+* R
direct_sum.to_semiring (λ i, add_submonoid_class.subtype (A i)) rfl (λ _ _ _ _, rfl)
def
direct_sum.coe_ring_hom
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_monoid", "direct_sum.to_semiring", "set_like.graded_monoid" ]
The canonical ring isomorphism between `⨁ i, A i` and `R`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_ring_hom_of [add_monoid ι] [set_like.graded_monoid A] (i : ι) (x : A i) : (coe_ring_hom A : _ →+* R) (of (λ i, A i) i x) = x
direct_sum.to_semiring_of _ _ _ _ _
lemma
direct_sum.coe_ring_hom_of
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_monoid", "direct_sum.to_semiring_of", "set_like.graded_monoid" ]
The canonical ring isomorphism between `⨁ i, A i` and `R`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_mul_apply [add_monoid ι] [set_like.graded_monoid A] [Π (i : ι) (x : A i), decidable (x ≠ 0)] (r r' : ⨁ i, A i) (n : ι) : ((r * r') n : R) = ∑ ij in (r.support ×ˢ r'.support).filter (λ ij : ι × ι, ij.1 + ij.2 = n), r ij.1 * r' ij.2
begin rw [mul_eq_sum_support_ghas_mul, dfinsupp.finset_sum_apply, add_submonoid_class.coe_finset_sum], simp_rw [coe_of_apply, ←finset.sum_filter, set_like.coe_ghas_mul], end
lemma
direct_sum.coe_mul_apply
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_monoid", "dfinsupp.finset_sum_apply", "filter", "set_like.coe_ghas_mul", "set_like.graded_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_mul_apply_eq_dfinsupp_sum [add_monoid ι] [set_like.graded_monoid A] [Π (i : ι) (x : A i), decidable (x ≠ 0)] (r r' : ⨁ i, A i) (n : ι) : ((r * r') n : R) = r.sum (λ i ri, r'.sum (λ j rj, if i + j = n then ri * rj else 0))
begin simp only [mul_eq_dfinsupp_sum, dfinsupp.sum_apply], iterate 2 { rw [dfinsupp.sum, add_submonoid_class.coe_finset_sum], congr, ext }, dsimp only, split_ifs, { subst h, rw of_eq_same, refl }, { rw of_eq_of_ne _ _ _ _ h, refl }, end
lemma
direct_sum.coe_mul_apply_eq_dfinsupp_sum
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_monoid", "dfinsupp.sum_apply", "set_like.graded_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_of_mul_apply_aux [add_monoid ι] [set_like.graded_monoid A] {i : ι} (r : A i) (r' : ⨁ i, A i) {j n : ι} (H : ∀ (x : ι), i + x = n ↔ x = j) : ((of _ i r * r') n : R) = r * r' j
begin classical, rw coe_mul_apply_eq_dfinsupp_sum, apply (dfinsupp.sum_single_index _).trans, swap, { simp_rw [zero_mem_class.coe_zero, zero_mul, if_t_t], exact dfinsupp.sum_zero }, simp_rw [dfinsupp.sum, H, finset.sum_ite_eq'], split_ifs, refl, rw [dfinsupp.not_mem_support_iff.mp h, zero_mem_class.coe_ze...
lemma
direct_sum.coe_of_mul_apply_aux
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_monoid", "mul_zero", "set_like.graded_monoid", "zero_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_mul_of_apply_aux [add_monoid ι] [set_like.graded_monoid A] (r : ⨁ i, A i) {i : ι} (r' : A i) {j n : ι} (H : ∀ (x : ι), x + i = n ↔ x = j) : ((r * of _ i r') n : R) = r j * r'
begin classical, rw [coe_mul_apply_eq_dfinsupp_sum, dfinsupp.sum_comm], apply (dfinsupp.sum_single_index _).trans, swap, { simp_rw [zero_mem_class.coe_zero, mul_zero, if_t_t], exact dfinsupp.sum_zero }, simp_rw [dfinsupp.sum, H, finset.sum_ite_eq'], split_ifs, refl, rw [dfinsupp.not_mem_support_iff.mp h, ...
lemma
direct_sum.coe_mul_of_apply_aux
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_monoid", "mul_zero", "set_like.graded_monoid", "zero_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_of_mul_apply_add [add_left_cancel_monoid ι] [set_like.graded_monoid A] {i : ι} (r : A i) (r' : ⨁ i, A i) (j : ι) : ((of _ i r * r') (i + j) : R) = r * r' j
coe_of_mul_apply_aux _ _ _ (λ x, ⟨λ h, add_left_cancel h, λ h, h ▸ rfl⟩)
lemma
direct_sum.coe_of_mul_apply_add
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_left_cancel_monoid", "set_like.graded_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_mul_of_apply_add [add_right_cancel_monoid ι] [set_like.graded_monoid A] (r : ⨁ i, A i) {i : ι} (r' : A i) (j : ι) : ((r * of _ i r') (j + i) : R) = r j * r'
coe_mul_of_apply_aux _ _ _ (λ x, ⟨λ h, add_right_cancel h, λ h, h ▸ rfl⟩)
lemma
direct_sum.coe_mul_of_apply_add
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_right_cancel_monoid", "set_like.graded_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_of_mul_apply_of_not_le {i : ι} (r : A i) (r' : ⨁ i, A i) (n : ι) (h : ¬ i ≤ n) : ((of _ i r * r') n : R) = 0
begin classical, rw coe_mul_apply_eq_dfinsupp_sum, apply (dfinsupp.sum_single_index _).trans, swap, { simp_rw [zero_mem_class.coe_zero, zero_mul, if_t_t], exact dfinsupp.sum_zero }, { rw [dfinsupp.sum, finset.sum_ite_of_false _ _ (λ x _ H, _), finset.sum_const_zero], exact h ((self_le_add_right i x).trans...
lemma
direct_sum.coe_of_mul_apply_of_not_le
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "zero_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_mul_of_apply_of_not_le (r : ⨁ i, A i) {i : ι} (r' : A i) (n : ι) (h : ¬ i ≤ n) : ((r * of _ i r') n : R) = 0
begin classical, rw [coe_mul_apply_eq_dfinsupp_sum, dfinsupp.sum_comm], apply (dfinsupp.sum_single_index _).trans, swap, { simp_rw [zero_mem_class.coe_zero, mul_zero, if_t_t], exact dfinsupp.sum_zero }, { rw [dfinsupp.sum, finset.sum_ite_of_false _ _ (λ x _ H, _), finset.sum_const_zero], exact h ((self_le...
lemma
direct_sum.coe_mul_of_apply_of_not_le
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "mul_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_mul_of_apply_of_le (r : ⨁ i, A i) {i : ι} (r' : A i) (n : ι) (h : i ≤ n) : ((r * of _ i r') n : R) = r (n - i) * r'
coe_mul_of_apply_aux _ _ _ (λ x, (eq_tsub_iff_add_eq_of_le h).symm)
lemma
direct_sum.coe_mul_of_apply_of_le
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "eq_tsub_iff_add_eq_of_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_of_mul_apply_of_le {i : ι} (r : A i) (r' : ⨁ i, A i) (n : ι) (h : i ≤ n) : ((of _ i r * r') n : R) = r * r' (n - i)
coe_of_mul_apply_aux _ _ _ (λ x, by rw [eq_tsub_iff_add_eq_of_le h, add_comm])
lemma
direct_sum.coe_of_mul_apply_of_le
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "eq_tsub_iff_add_eq_of_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_mul_of_apply (r : ⨁ i, A i) {i : ι} (r' : A i) (n : ι) [decidable (i ≤ n)] : ((r * of _ i r') n : R) = if i ≤ n then r (n - i) * r' else 0
by { split_ifs, exacts [coe_mul_of_apply_of_le _ _ _ n h, coe_mul_of_apply_of_not_le _ _ _ n h] }
lemma
direct_sum.coe_mul_of_apply
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_of_mul_apply {i : ι} (r : A i) (r' : ⨁ i, A i) (n : ι) [decidable (i ≤ n)] : ((of _ i r * r') n : R) = if i ≤ n then r * r' (n - i) else 0
by { split_ifs, exacts [coe_of_mul_apply_of_le _ _ _ n h, coe_of_mul_apply_of_not_le _ _ _ n h] }
lemma
direct_sum.coe_of_mul_apply
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
galgebra [add_monoid ι] [comm_semiring S] [semiring R] [algebra S R] (A : ι → submodule S R) [set_like.graded_monoid A] : direct_sum.galgebra S (λ i, A i)
{ to_fun := ((algebra.linear_map S R).cod_restrict (A 0) $ set_like.algebra_map_mem_graded A).to_add_monoid_hom, map_one := subtype.ext $ by exact (algebra_map S R).map_one, map_mul := λ x y, sigma.subtype_ext (add_zero 0).symm $ (algebra_map S R).map_mul _ _, commutes := λ r ⟨i, xi⟩, sigma.subtype_ext ((...
instance
submodule.galgebra
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_monoid", "algebra", "algebra.commutes", "algebra.linear_map", "algebra.smul_def", "algebra_map", "comm_semiring", "direct_sum.galgebra", "map_mul", "map_one", "semiring", "set_like.algebra_map_mem_graded", "set_like.graded_monoid", "sigma.subtype_ext", "submodule", "subtype.ext" ]
Build a `galgebra` instance for a collection of `submodule`s.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set_like.coe_galgebra_to_fun [add_monoid ι] [comm_semiring S] [semiring R] [algebra S R] (A : ι → submodule S R) [set_like.graded_monoid A] (s : S) : ↑(@direct_sum.galgebra.to_fun _ S (λ i, A i) _ _ _ _ _ _ _ s) = (algebra_map S R s : R)
rfl
lemma
submodule.set_like.coe_galgebra_to_fun
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_monoid", "algebra", "algebra_map", "comm_semiring", "semiring", "set_like.graded_monoid", "submodule" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_power_graded_monoid [comm_semiring S] [semiring R] [algebra S R] (p : submodule S R) : set_like.graded_monoid (λ i : ℕ, p ^ i)
{ one_mem := by { rw [←one_le, pow_zero], exact le_rfl }, mul_mem := λ i j p q hp hq, by { rw pow_add, exact submodule.mul_mem_mul hp hq } }
instance
submodule.nat_power_graded_monoid
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "algebra", "comm_semiring", "le_rfl", "pow_add", "pow_zero", "semiring", "set_like.graded_monoid", "submodule", "submodule.mul_mem_mul" ]
A direct sum of powers of a submodule of an algebra has a multiplicative structure.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
direct_sum.coe_alg_hom [add_monoid ι] [comm_semiring S] [semiring R] [algebra S R] (A : ι → submodule S R) [set_like.graded_monoid A] : (⨁ i, A i) →ₐ[S] R
direct_sum.to_algebra S _ (λ i, (A i).subtype) rfl (λ _ _ _ _, rfl) (λ _, rfl)
def
direct_sum.coe_alg_hom
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_monoid", "algebra", "comm_semiring", "direct_sum.to_algebra", "semiring", "set_like.graded_monoid", "submodule" ]
The canonical algebra isomorphism between `⨁ i, A i` and `R`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
submodule.supr_eq_to_submodule_range [add_monoid ι] [comm_semiring S] [semiring R] [algebra S R] (A : ι → submodule S R) [set_like.graded_monoid A] : (⨆ i, A i) = (direct_sum.coe_alg_hom A).range.to_submodule
(submodule.supr_eq_range_dfinsupp_lsum A).trans $ set_like.coe_injective rfl
lemma
submodule.supr_eq_to_submodule_range
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_monoid", "algebra", "comm_semiring", "direct_sum.coe_alg_hom", "semiring", "set_like.coe_injective", "set_like.graded_monoid", "submodule", "submodule.supr_eq_range_dfinsupp_lsum" ]
The supremum of submodules that form a graded monoid is a subalgebra, and equal to the range of `direct_sum.coe_alg_hom`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
direct_sum.coe_alg_hom_of [add_monoid ι] [comm_semiring S] [semiring R] [algebra S R] (A : ι → submodule S R) [set_like.graded_monoid A] (i : ι) (x : A i) : direct_sum.coe_alg_hom A (direct_sum.of (λ i, A i) i x) = x
direct_sum.to_semiring_of _ rfl (λ _ _ _ _, rfl) _ _
lemma
direct_sum.coe_alg_hom_of
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_monoid", "algebra", "comm_semiring", "direct_sum.coe_alg_hom", "direct_sum.of", "direct_sum.to_semiring_of", "semiring", "set_like.graded_monoid", "submodule" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set_like.is_homogeneous_zero_submodule [has_zero ι] [semiring S] [add_comm_monoid R] [module S R] (A : ι → submodule S R) : set_like.is_homogeneous A (0 : R)
⟨0, submodule.zero_mem _⟩
lemma
set_like.is_homogeneous_zero_submodule
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "add_comm_monoid", "module", "semiring", "set_like.is_homogeneous", "submodule", "submodule.zero_mem" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set_like.is_homogeneous.smul [comm_semiring S] [semiring R] [algebra S R] {A : ι → submodule S R} {s : S} {r : R} (hr : set_like.is_homogeneous A r) : set_like.is_homogeneous A (s • r)
let ⟨i, hi⟩ := hr in ⟨i, submodule.smul_mem _ _ hi⟩
lemma
set_like.is_homogeneous.smul
algebra.direct_sum
src/algebra/direct_sum/internal.lean
[ "algebra.algebra.operations", "algebra.algebra.subalgebra.basic", "algebra.direct_sum.algebra" ]
[ "algebra", "comm_semiring", "semiring", "set_like.is_homogeneous", "submodule", "submodule.smul_mem" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
smul_apply (b : R) (v : ⨁ i, M i) (i : ι) : (b • v) i = b • (v i)
dfinsupp.smul_apply _ _ _
lemma
direct_sum.smul_apply
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "dfinsupp.smul_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lmk : Π s : finset ι, (Π i : (↑s : set ι), M i.val) →ₗ[R] (⨁ i, M i)
dfinsupp.lmk
def
direct_sum.lmk
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "dfinsupp.lmk", "finset" ]
Create the direct sum given a family `M` of `R` modules indexed over `ι`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lof : Π i : ι, M i →ₗ[R] (⨁ i, M i)
dfinsupp.lsingle
def
direct_sum.lof
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "dfinsupp.lsingle" ]
Inclusion of each component into the direct sum.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lof_eq_of (i : ι) (b : M i) : lof R ι M i b = of M i b
rfl
lemma
direct_sum.lof_eq_of
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
single_eq_lof (i : ι) (b : M i) : dfinsupp.single i b = lof R ι M i b
rfl
lemma
direct_sum.single_eq_lof
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "dfinsupp.single" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_smul (s : finset ι) (c : R) (x) : mk M s (c • x) = c • mk M s x
(lmk R ι M s).map_smul c x
theorem
direct_sum.mk_smul
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "finset" ]
Scalar multiplication commutes with direct sums.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_smul (i : ι) (c : R) (x) : of M i (c • x) = c • of M i x
(lof R ι M i).map_smul c x
theorem
direct_sum.of_smul
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[]
Scalar multiplication commutes with the inclusion of each component into the direct sum.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
support_smul [Π (i : ι) (x : M i), decidable (x ≠ 0)] (c : R) (v : ⨁ i, M i) : (c • v).support ⊆ v.support
dfinsupp.support_smul _ _
lemma
direct_sum.support_smul
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "dfinsupp.support_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_module : (⨁ i, M i) →ₗ[R] N
dfinsupp.lsum ℕ φ
def
direct_sum.to_module
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "dfinsupp.lsum" ]
The linear map constructed using the universal property of the coproduct.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_to_module_eq_coe_to_add_monoid : (to_module R ι N φ : (⨁ i, M i) → N) = to_add_monoid (λ i, (φ i).to_add_monoid_hom)
rfl
lemma
direct_sum.coe_to_module_eq_coe_to_add_monoid
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[]
Coproducts in the categories of modules and additive monoids commute with the forgetful functor from modules to additive monoids.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_module_lof (i) (x : M i) : to_module R ι N φ (lof R ι M i x) = φ i x
to_add_monoid_of (λ i, (φ i).to_add_monoid_hom) i x
lemma
direct_sum.to_module_lof
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[]
The map constructed using the universal property gives back the original maps when restricted to each component.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_module.unique (f : ⨁ i, M i) : ψ f = to_module R ι N (λ i, ψ.comp $ lof R ι M i) f
to_add_monoid.unique ψ.to_add_monoid_hom f
theorem
direct_sum.to_module.unique
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[]
Every linear map from a direct sum agrees with the one obtained by applying the universal property to each of its components.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
linear_map_ext ⦃ψ ψ' : (⨁ i, M i) →ₗ[R] N⦄ (H : ∀ i, ψ.comp (lof R ι M i) = ψ'.comp (lof R ι M i)) : ψ = ψ'
dfinsupp.lhom_ext' H
theorem
direct_sum.linear_map_ext
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "dfinsupp.lhom_ext'" ]
Two `linear_map`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
lset_to_set (S T : set ι) (H : S ⊆ T) : (⨁ (i : S), M i) →ₗ[R] (⨁ (i : T), M i)
to_module R _ _ $ λ i, lof R T (λ (i : subtype T), M i) ⟨i, H i.prop⟩
def
direct_sum.lset_to_set
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[]
The inclusion of a subset of the direct summands into a larger subset of the direct summands, as a linear map.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
linear_equiv_fun_on_fintype [fintype ι] : (⨁ i, M i) ≃ₗ[R] (Π i, M i)
{ to_fun := coe_fn, map_add' := λ f g, by { ext, simp only [add_apply, pi.add_apply] }, map_smul' := λ c f, by { ext, simp only [dfinsupp.coe_smul, ring_hom.id_apply] }, .. dfinsupp.equiv_fun_on_fintype }
def
direct_sum.linear_equiv_fun_on_fintype
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "dfinsupp.coe_smul", "dfinsupp.equiv_fun_on_fintype", "fintype", "ring_hom.id_apply" ]
Given `fintype α`, `linear_equiv_fun_on_fintype R` is the natural `R`-linear equivalence between `⨁ i, M i` and `Π i, M i`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
linear_equiv_fun_on_fintype_lof [fintype ι] [decidable_eq ι] (i : ι) (m : M i) : (linear_equiv_fun_on_fintype R ι M) (lof R ι M i m) = pi.single i m
begin ext a, change (dfinsupp.equiv_fun_on_fintype (lof R ι M i m)) a = _, convert _root_.congr_fun (dfinsupp.equiv_fun_on_fintype_single i m) a, end
lemma
direct_sum.linear_equiv_fun_on_fintype_lof
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "dfinsupp.equiv_fun_on_fintype", "dfinsupp.equiv_fun_on_fintype_single", "fintype" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
linear_equiv_fun_on_fintype_symm_single [fintype ι] [decidable_eq ι] (i : ι) (m : M i) : (linear_equiv_fun_on_fintype R ι M).symm (pi.single i m) = lof R ι M i m
begin ext a, change (dfinsupp.equiv_fun_on_fintype.symm (pi.single i m)) a = _, rw (dfinsupp.equiv_fun_on_fintype_symm_single i m), refl end
lemma
direct_sum.linear_equiv_fun_on_fintype_symm_single
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "dfinsupp.equiv_fun_on_fintype_symm_single", "fintype" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
linear_equiv_fun_on_fintype_symm_coe [fintype ι] (f : ⨁ i, M i) : (linear_equiv_fun_on_fintype R ι M).symm f = f
by { ext, simp [linear_equiv_fun_on_fintype], }
lemma
direct_sum.linear_equiv_fun_on_fintype_symm_coe
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "fintype" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lid (M : Type v) (ι : Type* := punit) [add_comm_monoid M] [module R M] [unique ι] : (⨁ (_ : ι), M) ≃ₗ[R] M
{ .. direct_sum.id M ι, .. to_module R ι M (λ i, linear_map.id) }
def
direct_sum.lid
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "add_comm_monoid", "direct_sum.id", "linear_map.id", "module", "unique" ]
The natural linear equivalence between `⨁ _ : ι, M` and `M` when `unique ι`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
component (i : ι) : (⨁ i, M i) →ₗ[R] M i
dfinsupp.lapply i
def
direct_sum.component
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "dfinsupp.lapply" ]
The projection map onto one component, as a linear map.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
apply_eq_component (f : ⨁ i, M i) (i : ι) : f i = component R ι M i f
rfl
lemma
direct_sum.apply_eq_component
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ext {f g : ⨁ i, M i} (h : ∀ i, component R ι M i f = component R ι M i g) : f = g
dfinsupp.ext h
lemma
direct_sum.ext
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "dfinsupp.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ext_iff {f g : ⨁ i, M i} : f = g ↔ ∀ i, component R ι M i f = component R ι M i g
⟨λ h _, by rw h, ext R⟩
lemma
direct_sum.ext_iff
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lof_apply (i : ι) (b : M i) : ((lof R ι M i) b) i = b
dfinsupp.single_eq_same
lemma
direct_sum.lof_apply
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "dfinsupp.single_eq_same" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
component.lof_self (i : ι) (b : M i) : component R ι M i ((lof R ι M i) b) = b
lof_apply R i b
lemma
direct_sum.component.lof_self
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
component.of (i j : ι) (b : M j) : component R ι M i ((lof R ι M j) b) = if h : j = i then eq.rec_on h b else 0
dfinsupp.single_apply
lemma
direct_sum.component.of
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "dfinsupp.single_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lequiv_congr_left (h : ι ≃ κ) : (⨁ i, M i) ≃ₗ[R] ⨁ k, M (h.symm k)
{ map_smul' := dfinsupp.comap_domain'_smul _ _, ..equiv_congr_left h }
def
direct_sum.lequiv_congr_left
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "dfinsupp.comap_domain'_smul" ]
Reindexing terms of a direct sum is linear.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lequiv_congr_left_apply (h : ι ≃ κ) (f : ⨁ i, M i) (k : κ) : lequiv_congr_left R h f k = f (h.symm k)
equiv_congr_left_apply _ _ _
lemma
direct_sum.lequiv_congr_left_apply
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma_lcurry : (⨁ (i : Σ i, _), δ i.1 i.2) →ₗ[R] ⨁ i j, δ i j
{ map_smul' := λ r, by convert (@dfinsupp.sigma_curry_smul _ _ _ δ _ _ _ r), ..sigma_curry }
def
direct_sum.sigma_lcurry
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "dfinsupp.sigma_curry_smul" ]
`curry` as a linear map.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma_lcurry_apply (f : ⨁ (i : Σ i, _), δ i.1 i.2) (i : ι) (j : α i) : sigma_lcurry R f i j = f ⟨i, j⟩
sigma_curry_apply f i j
lemma
direct_sum.sigma_lcurry_apply
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma_luncurry [Π i, decidable_eq (α i)] [Π i j, decidable_eq (δ i j)] : (⨁ i j, δ i j) →ₗ[R] ⨁ (i : Σ i, _), δ i.1 i.2
{ map_smul' := dfinsupp.sigma_uncurry_smul, ..sigma_uncurry }
def
direct_sum.sigma_luncurry
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "dfinsupp.sigma_uncurry_smul" ]
`uncurry` as a linear map.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma_luncurry_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_luncurry R f ⟨i, j⟩ = f i j
sigma_uncurry_apply f i j
lemma
direct_sum.sigma_luncurry_apply
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma_lcurry_equiv [Π i, decidable_eq (α i)] [Π i j, decidable_eq (δ i j)] : (⨁ (i : Σ i, _), δ i.1 i.2) ≃ₗ[R] ⨁ i j, δ i j
{ ..sigma_curry_equiv, ..sigma_lcurry R }
def
direct_sum.sigma_lcurry_equiv
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[]
`curry_equiv` as a linear equiv.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lequiv_prod_direct_sum : (⨁ i, α i) ≃ₗ[R] α none × ⨁ i, α (some i)
{ map_smul' := dfinsupp.equiv_prod_dfinsupp_smul, ..add_equiv_prod_direct_sum }
def
direct_sum.lequiv_prod_direct_sum
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "dfinsupp.equiv_prod_dfinsupp_smul" ]
Linear isomorphism obtained by separating the term of index `none` of a direct sum over `option ι`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_linear_map : (⨁ i, A i) →ₗ[R] M
to_module R ι M (λ i, (A i).subtype)
def
direct_sum.coe_linear_map
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[]
The canonical embedding from `⨁ i, A i` to `M` where `A` is a collection of `submodule R M` indexed by `ι`. This is `direct_sum.coe_add_monoid_hom` as a `linear_map`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_linear_map_of (i : ι) (x : A i) : direct_sum.coe_linear_map A (of (λ i, A i) i x) = x
to_add_monoid_of _ _ _
lemma
direct_sum.coe_linear_map_of
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "direct_sum.coe_linear_map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_internal.submodule_supr_eq_top (h : is_internal A) : supr A = ⊤
begin rw [submodule.supr_eq_range_dfinsupp_lsum, linear_map.range_eq_top], exact function.bijective.surjective h, end
lemma
direct_sum.is_internal.submodule_supr_eq_top
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "function.bijective.surjective", "linear_map.range_eq_top", "submodule.supr_eq_range_dfinsupp_lsum", "supr" ]
If a direct sum of submodules is internal then the submodules span the module.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_internal.submodule_independent (h : is_internal A) : complete_lattice.independent A
complete_lattice.independent_of_dfinsupp_lsum_injective _ h.injective
lemma
direct_sum.is_internal.submodule_independent
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "complete_lattice.independent", "complete_lattice.independent_of_dfinsupp_lsum_injective" ]
If a direct sum of submodules is internal then the submodules are independent.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_internal.collected_basis (h : is_internal A) {α : ι → Type*} (v : Π i, basis (α i) R (A i)) : basis (Σ i, α i) R M
{ repr := (linear_equiv.of_bijective (direct_sum.coe_linear_map A) h).symm ≪≫ₗ (dfinsupp.map_range.linear_equiv (λ i, (v i).repr)) ≪≫ₗ (sigma_finsupp_lequiv_dfinsupp R).symm }
def
direct_sum.is_internal.collected_basis
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "basis", "dfinsupp.map_range.linear_equiv", "direct_sum.coe_linear_map", "linear_equiv.of_bijective", "sigma_finsupp_lequiv_dfinsupp" ]
Given an internal direct sum decomposition of a module `M`, and a basis for each of the components of the direct sum, the disjoint union of these bases is a basis for `M`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_internal.collected_basis_coe (h : is_internal A) {α : ι → Type*} (v : Π i, basis (α i) R (A i)) : ⇑(h.collected_basis v) = λ a : Σ i, (α i), ↑(v a.1 a.2)
begin funext a, simp only [is_internal.collected_basis, to_module, coe_linear_map, add_equiv.to_fun_eq_coe, basis.coe_of_repr, basis.repr_symm_apply, dfinsupp.lsum_apply_apply, dfinsupp.map_range.linear_equiv_apply, dfinsupp.map_range.linear_equiv_symm, dfinsupp.map_range_single, finsupp.total_single, l...
lemma
direct_sum.is_internal.collected_basis_coe
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "basis", "basis.coe_of_repr", "basis.repr_symm_apply", "dfinsupp.map_range.linear_equiv_symm", "dfinsupp.map_range_single", "dfinsupp.sum_add_hom_single", "finsupp.total_single", "linear_equiv.of_bijective_apply", "linear_equiv.symm_symm", "linear_equiv.symm_trans_apply", "one_smul", "sigma_fi...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_internal.collected_basis_mem (h : is_internal A) {α : ι → Type*} (v : Π i, basis (α i) R (A i)) (a : Σ i, α i) : h.collected_basis v a ∈ A a.1
by simp
lemma
direct_sum.is_internal.collected_basis_mem
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "basis" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_internal.is_compl {A : ι → submodule R M} {i j : ι} (hij : i ≠ j) (h : (set.univ : set ι) = {i, j}) (hi : is_internal A) : is_compl (A i) (A j)
⟨hi.submodule_independent.pairwise_disjoint hij, codisjoint_iff.mpr $ eq.symm $ hi.submodule_supr_eq_top.symm.trans $ by rw [←Sup_pair, supr, ←set.image_univ, h, set.image_insert_eq, set.image_singleton]⟩
lemma
direct_sum.is_internal.is_compl
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "is_compl", "set.image_insert_eq", "set.image_singleton", "submodule", "supr" ]
When indexed by only two distinct elements, `direct_sum.is_internal` implies the two submodules are complementary. Over a `ring R`, this is true as an iff, as `direct_sum.is_internal_iff_is_compl`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_internal_submodule_of_independent_of_supr_eq_top {A : ι → submodule R M} (hi : complete_lattice.independent A) (hs : supr A = ⊤) : is_internal A
⟨hi.dfinsupp_lsum_injective, linear_map.range_eq_top.1 $ (submodule.supr_eq_range_dfinsupp_lsum _).symm.trans hs⟩
lemma
direct_sum.is_internal_submodule_of_independent_of_supr_eq_top
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "complete_lattice.independent", "submodule", "submodule.supr_eq_range_dfinsupp_lsum", "supr" ]
Note that this is not generally true for `[semiring R]`; see `complete_lattice.independent.dfinsupp_lsum_injective` for details.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_internal_submodule_iff_independent_and_supr_eq_top (A : ι → submodule R M) : is_internal A ↔ complete_lattice.independent A ∧ supr A = ⊤
⟨λ i, ⟨i.submodule_independent, i.submodule_supr_eq_top⟩, and.rec is_internal_submodule_of_independent_of_supr_eq_top⟩
lemma
direct_sum.is_internal_submodule_iff_independent_and_supr_eq_top
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "complete_lattice.independent", "submodule", "supr" ]
`iff` version of `direct_sum.is_internal_submodule_of_independent_of_supr_eq_top`, `direct_sum.is_internal.independent`, and `direct_sum.is_internal.supr_eq_top`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_internal_submodule_iff_is_compl (A : ι → submodule R M) {i j : ι} (hij : i ≠ j) (h : (set.univ : set ι) = {i, j}) : is_internal A ↔ is_compl (A i) (A j)
begin have : ∀ k, k = i ∨ k = j := λ k, by simpa using set.ext_iff.mp h k, rw [is_internal_submodule_iff_independent_and_supr_eq_top, supr, ←set.image_univ, h, set.image_insert_eq, set.image_singleton, Sup_pair, complete_lattice.independent_pair hij this], exact ⟨λ ⟨hd, ht⟩, ⟨hd, codisjoint_iff.mpr ht⟩, λ...
lemma
direct_sum.is_internal_submodule_iff_is_compl
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "Sup_pair", "complete_lattice.independent_pair", "is_compl", "set.image_insert_eq", "set.image_singleton", "submodule", "supr" ]
If a collection of submodules has just two indices, `i` and `j`, then `direct_sum.is_internal` is equivalent to `is_compl`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_internal.add_submonoid_independent {M : Type*} [add_comm_monoid M] {A : ι → add_submonoid M} (h : is_internal A) : complete_lattice.independent A
complete_lattice.independent_of_dfinsupp_sum_add_hom_injective _ h.injective
lemma
direct_sum.is_internal.add_submonoid_independent
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "add_comm_monoid", "add_submonoid", "complete_lattice.independent", "complete_lattice.independent_of_dfinsupp_sum_add_hom_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_internal.add_subgroup_independent {M : Type*} [add_comm_group M] {A : ι → add_subgroup M} (h : is_internal A) : complete_lattice.independent A
complete_lattice.independent_of_dfinsupp_sum_add_hom_injective' _ h.injective
lemma
direct_sum.is_internal.add_subgroup_independent
algebra.direct_sum
src/algebra/direct_sum/module.lean
[ "algebra.direct_sum.basic", "linear_algebra.dfinsupp" ]
[ "add_comm_group", "add_subgroup", "complete_lattice.independent", "complete_lattice.independent_of_dfinsupp_sum_add_hom_injective'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
gnon_unital_non_assoc_semiring [has_add ι] [Π i, add_comm_monoid (A i)] extends graded_monoid.ghas_mul A
(mul_zero : ∀ {i j} (a : A i), mul a (0 : A j) = 0) (zero_mul : ∀ {i j} (b : A j), mul (0 : A i) b = 0) (mul_add : ∀ {i j} (a : A i) (b c : A j), mul a (b + c) = mul a b + mul a c) (add_mul : ∀ {i j} (a b : A i) (c : A j), mul (a + b) c = mul a c + mul b c)
class
direct_sum.gnon_unital_non_assoc_semiring
algebra.direct_sum
src/algebra/direct_sum/ring.lean
[ "algebra.graded_monoid", "algebra.direct_sum.basic" ]
[ "add_comm_monoid", "graded_monoid.ghas_mul", "mul_zero", "zero_mul" ]
A graded version of `non_unital_non_assoc_semiring`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
gsemiring [add_monoid ι] [Π i, add_comm_monoid (A i)] extends gnon_unital_non_assoc_semiring A, graded_monoid.gmonoid A
(nat_cast : ℕ → A 0) (nat_cast_zero : nat_cast 0 = 0) (nat_cast_succ : ∀ n : ℕ, nat_cast (n + 1) = nat_cast n + graded_monoid.ghas_one.one)
class
direct_sum.gsemiring
algebra.direct_sum
src/algebra/direct_sum/ring.lean
[ "algebra.graded_monoid", "algebra.direct_sum.basic" ]
[ "add_comm_monoid", "add_monoid", "graded_monoid.gmonoid" ]
A graded version of `semiring`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
gcomm_semiring [add_comm_monoid ι] [Π i, add_comm_monoid (A i)] extends gsemiring A, graded_monoid.gcomm_monoid A
class
direct_sum.gcomm_semiring
algebra.direct_sum
src/algebra/direct_sum/ring.lean
[ "algebra.graded_monoid", "algebra.direct_sum.basic" ]
[ "add_comm_monoid", "graded_monoid.gcomm_monoid" ]
A graded version of `comm_semiring`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
gring [add_monoid ι] [Π i, add_comm_group (A i)] extends gsemiring A
(int_cast : ℤ → A 0) (int_cast_of_nat : ∀ n : ℕ, int_cast n = nat_cast n) (int_cast_neg_succ_of_nat : ∀ n : ℕ, int_cast (-(n+1 : ℕ)) = -nat_cast (n+1 : ℕ))
class
direct_sum.gring
algebra.direct_sum
src/algebra/direct_sum/ring.lean
[ "algebra.graded_monoid", "algebra.direct_sum.basic" ]
[ "add_comm_group", "add_monoid" ]
A graded version of `ring`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
gcomm_ring [add_comm_monoid ι] [Π i, add_comm_group (A i)] extends gring A, gcomm_semiring A
class
direct_sum.gcomm_ring
algebra.direct_sum
src/algebra/direct_sum/ring.lean
[ "algebra.graded_monoid", "algebra.direct_sum.basic" ]
[ "add_comm_group", "add_comm_monoid" ]
A graded version of `comm_ring`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_eq_of_graded_monoid_eq {A : ι → Type*} [Π (i : ι), add_comm_monoid (A i)] {i j : ι} {a : A i} {b : A j} (h : graded_monoid.mk i a = graded_monoid.mk j b) : direct_sum.of A i a = direct_sum.of A j b
dfinsupp.single_eq_of_sigma_eq h
lemma
direct_sum.of_eq_of_graded_monoid_eq
algebra.direct_sum
src/algebra/direct_sum/ring.lean
[ "algebra.graded_monoid", "algebra.direct_sum.basic" ]
[ "add_comm_monoid", "dfinsupp.single_eq_of_sigma_eq", "direct_sum.of", "graded_monoid.mk" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
gmul_hom {i j} : A i →+ A j →+ A (i + j)
{ to_fun := λ a, { to_fun := λ b, graded_monoid.ghas_mul.mul a b, map_zero' := gnon_unital_non_assoc_semiring.mul_zero _, map_add' := gnon_unital_non_assoc_semiring.mul_add _ }, map_zero' := add_monoid_hom.ext $ λ a, gnon_unital_non_assoc_semiring.zero_mul a, map_add' := λ a₁ a₂, add_monoid_hom.ext $ λ b,...
def
direct_sum.gmul_hom
algebra.direct_sum
src/algebra/direct_sum/ring.lean
[ "algebra.graded_monoid", "algebra.direct_sum.basic" ]
[]
The piecewise multiplication from the `has_mul` instance, as a bundled homomorphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_hom : (⨁ i, A i) →+ (⨁ i, A i) →+ ⨁ i, A i
direct_sum.to_add_monoid $ λ i, add_monoid_hom.flip $ direct_sum.to_add_monoid $ λ j, add_monoid_hom.flip $ (direct_sum.of A _).comp_hom.comp $ gmul_hom A
def
direct_sum.mul_hom
algebra.direct_sum
src/algebra/direct_sum/ring.lean
[ "algebra.graded_monoid", "algebra.direct_sum.basic" ]
[ "direct_sum.of", "direct_sum.to_add_monoid", "mul_hom" ]
The multiplication from the `has_mul` instance, as a bundled homomorphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_hom_of_of {i j} (a : A i) (b : A j) : mul_hom A (of _ i a) (of _ j b) = of _ (i + j) (graded_monoid.ghas_mul.mul a b)
begin unfold mul_hom, rw [to_add_monoid_of, flip_apply, to_add_monoid_of, flip_apply, coe_comp, function.comp_app, comp_hom_apply_apply, coe_comp, function.comp_app, gmul_hom_apply_apply], end
lemma
direct_sum.mul_hom_of_of
algebra.direct_sum
src/algebra/direct_sum/ring.lean
[ "algebra.graded_monoid", "algebra.direct_sum.basic" ]
[ "mul_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83