20/01/08 12:09:40.94 1QCooAdl.net
>>173 追加
species って、nLabでは圏論なんだけど
望月 IUT4 §3では、ZFCの集合論みたく書いてある
はて はて？ （＾＾；
URLﾘﾝｸ(ncatlab.org)
nLab
species
(抜粋)
1. Idea
A (combinatorial) species is a presheaf or higher categorical presheaf on the groupoid core(FinSet), the permutation groupoid.
A species is a symmetric sequence by another name. Meaning: they are categorically equivalent notions.
2. Definition
1-categorical
2-categorical
(∞,1) -categorical
Operations on species
There are in fact 5 important monoidal structures on the category of species.