Higher categories through nerves and inner horns
Research context
postgraduate concept · established · As of 2026-10-10
The nerve of an ordinary category has n-simplices given by chains of n composable arrows; inner horns have unique fillers encoding composition.
Key knowledge
The nerve of an ordinary category has n-simplices given by chains of n composable arrows; inner horns have unique fillers encoding composition. A quasi-category weakens this to existence of inner-horn fillers, representing an (infinity,1)-category with higher coherent equivalences. A Kan complex fills all horns and models an infinity-groupoid. These are specified models of higher structure, not a claim that every notion of higher category is identical without comparison theorems.
Conditions and scope
- The construction is in simplicial sets; inner horns Lambda-k[n] use n≥2 and 0<k<n.
- Composition in a quasi-category is not a chosen strictly unique operation on all edges; its coherent equivalence data matters.
Sources · 1
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Evidence and review
Author checked this English statement, displayed equation where present and stated hypotheses against these source locations: §1.1 simplicial sets, inner horns, ordinary nerve, homotopy category and Kan complexes. The check is bounded to the recorded claims; no complete proof reconstruction, software proof replay or universal literature completeness is claimed.
2026-10-10 · Author source-body/statement/equation/domain check, with graph associations scoped individually. Separate independent content/source/inventory review is required before branch closure.
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