Operations on submonoids
In this file we define various operations on submonoids and monoid_homs.
Main definitions
Conversion between multiplicative and additive definitions
submonoid.to_add_submonoid,submonoid.of_add_submonoid,add_submonoid.to_submonoid,add_submonoid.of_submonoid: convert between multiplicative and additive submonoids ofM,multiplicative M, andadditive M.submonoid.add_submonoid_equiv: equivalence betweensubmonoid Mandadd_submonoid (additive M).
(Commutative) monoid structure on a submonoid
submonoid.to_monoid,submonoid.to_comm_monoid: a submonoid inherits a (commutative) monoid structure.
Operations on submonoids
submonoid.comap: preimage of a submonoid under a monoid homomorphism as a submonoid of the domain;submonoid.map: image of a submonoid under a monoid homomorphism as a submonoid of the codomain;submonoid.prod: product of two submonoidss : submonoid Mandt : submonoid Nas a submonoid ofM × N;
Monoid homomorphisms between submonoid
submonoid.subtype: embedding of a submonoid into the ambient monoid.submonoid.inclusion: given two submonoidsS,Tsuch thatS ≤ T,S.inclusion Tis the inclusion ofSintoTas a monoid homomorphism;mul_equiv.submonoid_congr: converts a proof ofS = Tinto a monoid isomorphism betweenSandT.submonoid.prod_equiv: monoid isomorphism betweens.prod tands × t;
Operations on monoid_homs
monoid_hom.mrange: range of a monoid homomorphism as a submonoid of the codomain;monoid_hom.mrestrict: restrict a monoid homomorphism to a submonoid;monoid_hom.cod_mrestrict: restrict the codomain of a monoid homomorphism to a submonoid;monoid_hom.mrange_restrict: restrict a monoid homomorphism to its range;
Tags
submonoid, range, product, map, comap
Conversion to/from additive/multiplicative
Map from submonoids of monoid M to add_submonoids of additive M.
Map from add_submonoids of additive M to submonoids of M.
Map from add_submonoids of add_monoid M to submonoids of multiplicative M.
Map from submonoids of multiplicative M to add_submonoids of add_monoid M.
Submonoids of monoid M are isomorphic to additive submonoids of additive M.
Equations
- submonoid.add_submonoid_equiv M = {to_fun := submonoid.to_add_submonoid _inst_4, inv_fun := submonoid.of_add_submonoid _inst_4, left_inv := _, right_inv := _}
comap and map
The preimage of an add_submonoid along an add_monoid homomorphism is an
add_submonoid.
The image of an add_submonoid along an add_monoid homomorphism is
an add_submonoid.
map f and comap f form a galois_coinsertion when f is injective.
Equations
map f and comap f form a galois_insertion when f is surjective.
Equations
An add_submonoid of an add_monoid inherits an addition.
An add_submonoid of an add_monoid inherits a zero.
An add_submonoid of an add_monoid inherits an add_monoid
structure.
A submonoid of a monoid inherits a monoid structure.
Equations
- S.to_monoid = function.injective.monoid coe _ _ _
An add_submonoid of an add_comm_monoid is
an add_comm_monoid.
The natural monoid hom from an add_submonoid of add_monoid M to M.
Given add_submonoids s, t of add_monoids A, B respectively, s × t
as an add_submonoid of A × B.
The product of additive submonoids is isomorphic to their product as additive monoids
The product of submonoids is isomorphic to their product as monoids.
The range of an add_monoid_hom is an add_submonoid.
The range of a monoid homomorphism is a submonoid.
Equations
- f.mrange = submonoid.map f ⊤
The range of a surjective monoid hom is the whole of the codomain.
The range of a surjective add_monoid hom is the whole of the codomain.
The image under an add_monoid hom of the add_submonoid generated by a set equals
the add_submonoid generated by the image of the set.
The image under a monoid hom of the submonoid generated by a set equals the submonoid generated by the image of the set.
Restriction of an add_monoid hom to an add_submonoid of the domain.
Restriction of a monoid hom to a submonoid of the codomain.
Restriction of an add_monoid hom to an add_submonoid of the codomain.
Restriction of an add_monoid hom to its range interpreted as a submonoid.
Restriction of a monoid hom to its range interpreted as a submonoid.
Equations
- f.mrange_restrict = f.cod_mrestrict f.mrange _
The add_monoid hom associated to an inclusion of submonoids.
The monoid hom associated to an inclusion of submonoids.
Equations
- submonoid.inclusion h = S.subtype.cod_mrestrict T _
Makes the identity isomorphism from a proof that two submonoids of a multiplicative monoid are equal.
Equations
- mul_equiv.submonoid_congr h = {to_fun := (equiv.set_congr _).to_fun, inv_fun := (equiv.set_congr _).inv_fun, left_inv := _, right_inv := _, map_mul' := _}
Makes the identity additive isomorphism from a proof two submonoids of an additive monoid are equal.