Combinatorial Species - Generalizations

Generalizations

Species need not be functors from to : other categories can replace these, to obtain species of a different nature.

• A species in k sorts is a functor . Here, the structures produced can have elements drawn from distinct sources.
• A functor to, the category of R-weighted sets for R a ring of power series, is a weighted species.
• A tensorial species is a functor into the category of finite-dimensional vector spaces over the complex numbers.