Structure

simplex category

Notation Δ\Delta Objects the non-empty ordered sets [n]≔{0<⋯<n}[n] \coloneqq \{0 < \cdots < n\} for n∈Nn \in \IN Morphisms order-preserving maps Related FinOrd\FinOrd, Set≠∅\Setne, sSet\sSet, Δ≤1\Delta^{\leq 1} External nLab link
The simplex category is a skeleton of FinOrd∖{∅}\FinOrd \setminus \{\varnothing\}. It plays an important role in topology and is used to define the category of simplicial sets. In older literature, it is also called the simplicial category, but nowadays this term usually refers to a simplicially enriched category.

Satisfied properties

Assigned properties

Deduced properties

Unsatisfied properties

Assigned properties

Deduced properties*

*This also uses the deduced satisfied properties.

Unknown properties

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Special objects

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Special morphisms

  • isomorphisms: bijective order-preserving maps
  • monomorphisms: injective order-preserving maps
  • epimorphisms: surjective order-preserving maps
  • regular monomorphisms: same as monomorphisms
  • regular epimorphisms: same as epimorphisms