Category theory is more and more used in studying abstract data types. Since long time, some authors used the notion of sketch to study the syntax and semantics of mathematical structures. This notion, introduced and developed by Ehresmann, is more powerful than the signature one, since it uses limits in categorical sense. Indeed, the signature approach uses nothing but products, while the notion of sketch allows not only to specify algebraic structures but also non algebraic ones such as fields.
Lire maintenant ?