Recall that **extra degeneracies** for an augmented simplicial set $X$ are maps $s_0\colon X_n \to X_{n+1}$ for $n=-1,0,1,2,\ldots$ which satisfy the usual simplicial identities with respect to the existing $d_i$, $s_i$. This definition clearly works for simplicial objects in pretty much an arbitrary category.


A simplicial set with extra degeneracies and $X_{-1} = \ast$ (call these, in abuse of nomenclature, reduced) is contractible. In fact, given enough structure on an ambient category $C$, one can sensibly talk about homotopy of simplicial objects in $C$ (for example, one can say when $sC$ is a category with cofibrant objects, and has a notion of homotopy of maps).

Tim Porter points out [here](https://lists.lehigh.edu/pipermail/algtop-l/2008q4/000256.html) an observation (probably due originally to Lawvere) that if we define $\Delta_{last}$ to be the subcategory of $\Delta$ of non-empty finite ordinals whose morphisms preserve the last element in each ordinal, then $C$-valued presheaves on $\Delta_{last}$ are equivalent to augmented simplicial objects with extra degeneracies. One can then consider, if $C$ has a terminal object, the subcategory of 'reduced' presheaves. Presumably we can consider these as functors preserving something (terminal object? Please excuse my laziness for not checking this, it's not crucial to the question).

So my question is this: is it reasonable to think of reduced presheaves on $\Delta_{last}$ as being contractible for any $C$ with terminal object? Certainly, ignoring size issues, we can think of such things as being contractible after we embed them in the category of simplicial sets in $Pre(C)$, if not some smaller (co)completion category.

Secondarily, can I get away with saying a reduced presheaf on $\Delta_{last}$ "is a contractible simplicial object?" If I define such as thing for $C$ with insufficient structure to support homotopies _as_ a reduced presheaf on $\Delta_{last}$ then it all becomes a bit tautological.