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Summary A semigroup with an identity element.
Record metadata
Canonical name Monoid
Concept ID monoid
Content version 2.3.0
Alternate terminology No alternate terminology is currently authored for this record. Data binary operation identity element e e e Axioms / constraints associativity e ⋅ x = x = x ⋅ e e\cdot x = x = x\cdot e e ⋅ x = x = x ⋅ e Notes The identity, if it exists in a semigroup, is unique; monoidhood is therefore an existence property rather than freely chosen additional data.
Incoming relations (arrows to this concept) Each relation below ends at this concept.
This is an authored directed relation from the source endpoint to the target endpoint.
Relation ID e_semigroup_monoid
Relation type Impose axiom impose-axiom
Direction source → target
Endpoint roles source: Builds toward; target: Built from
Authored annotation require an identity Authored explanation Select semigroups in which a two-sided identity exists; it is then unique.
How to interpret this relation type Keep the existing data and select the subclass satisfying an additional law, existence condition, finiteness condition, or other property.
Outgoing relations (arrows from this concept) Each relation below starts at this concept.
This is an authored directed relation from the source endpoint to the target endpoint.
Relation ID e_monoid_comm
Relation type Impose axiom impose-axiom
Direction source → target
Endpoint roles source: Builds toward; target: Built from
Authored annotation + commutativity Authored explanation Require x y = y x xy=yx x y = y x .
How to interpret this relation type Keep the existing data and select the subclass satisfying an additional law, existence condition, finiteness condition, or other property.
This is an authored directed relation from the source endpoint to the target endpoint.
Relation ID e_monoid_group
Relation type Impose axiom impose-axiom
Direction source → target
Endpoint roles source: Builds toward; target: Built from
Authored annotation + inverses Authored explanation Require every element to have a two-sided inverse.
How to interpret this relation type Keep the existing data and select the subclass satisfying an additional law, existence condition, finiteness condition, or other property.
This is an authored directed relation from the source endpoint to the target endpoint.
Relation ID j_residuated__monoid
Relation type Combine compatible structures combine-compatible
Direction source → target
Endpoint roles source: Builds toward; target: Built from
Authored annotation multiplication Authored explanation Supply the Monoid structure as one jointly required input.
How to interpret this relation type Feed several structures into a construction junction and impose compatibility between them.
This is an authored directed relation from the source endpoint to the target endpoint.
Relation ID e_monoid_jsemi
Relation type Combine compatible structures combine-compatible
Direction source → target
Endpoint roles source: Builds toward; target: Built from
Authored annotation use as multiplication Authored explanation Supply the multiplicative monoid.
How to interpret this relation type Feed several structures into a construction junction and impose compatibility between them.
This is an authored directed relation from the source endpoint to the target endpoint.
Relation ID j_top_monoid__monoid
Relation type Combine compatible structures combine-compatible
Direction source → target
Endpoint roles source: Builds toward; target: Built from
Authored annotation monoid law Authored explanation Supply the Monoid structure as one jointly required input.
How to interpret this relation type Feed several structures into a construction junction and impose compatibility between them.
This is an authored directed relation from the source endpoint to the target endpoint.
Relation ID e_monoid_one_object_category
Relation type Representation / equivalence representation-equivalence
Direction source → target
Endpoint roles source: Representation / equivalence with; target: Representation / equivalence with
Authored annotation view as a one-object category Authored explanation A monoid is precisely a category with one object: monoid elements are endomorphisms and multiplication is composition.
How to interpret this relation type Reinterpret an object, pass to an equivalent presentation, or relate canonically corresponding structures; the carrier may change.