On the monoids of homomorphisms of semigroups with unity
Luděk Kučera · Czech digital mathematics library · 1982
Ab9tract: It is proved that -any semigroup with unity and zero element is isomorphic to a semigroup of endomorphisms of some monoid (i.e» semigroup with unity), -any small category with zero morphisms is isomorphic to a small full subcategory of the category of monoids and their homomorphisms, -any concrete category with zero morphisms is isomorphic to a full subcategory of the category of monoids and their homomorphisms, provided the non-existence of measurable cardinals is supposed. Key words; Category theory,