## I.1 (definitions of $\infty$-categories) $\infty$-categories as simplicial sets $\infty$-categories as categories enriched in 1. $sSet$ 1. $Top_CG$ ## I.2 (basic $\infty$-category theory) ### 1.2.3 (the homotopy category of a simplicial set) ### 1.2.4 (objects and morphisms in an $\infty$-category) ### 1.2.5 ($\infty$-groupoids) ### 1.2.6 (homotopy commutativity and homotopy coherence) ### 1.2.7 (functors between $\infty$-categories) Proposition 1.2.7.3 ### 1.2.10, 1.2.11, 1.2.16 ## Appendix A.2 (model categories and their homotopy categories)