Steve Awodey の Category Theory を読む シリーズトップ 5.2 Pullbacks Proposition 5.5 Exercise 3 5.3 Properties of pullbacks Two pullbacks lemma Proposition 5.10 Example 5.13 5.4 Limits Proposition 5.14 5.6 Colimits Direct limits of groups …

Steve Awodey の Category Theory を読む シリーズトップ 4.1 Groups in a category Corollary 4.6 4.2 The category of groups is an equivalence relation Corollary 4.11 Cokernels are special coequalizers 4.3 Groups as categories composition of th…