Contractible simplicial objects
Michael Barr, John F. Kennison, Robert M. Raphael (2019)
Commentationes Mathematicae Universitatis Carolinae
Similarity:
We raise the question of when a simplicial object in a catetgory is deemed contractible. The literature offers three definitions. One is the existence of an “extra degeneracy”, indexed by , which does not quite live up to the name. This can be strengthened to a “strong extra degeneracy". Another possibility is that it be homotopic to a constant simplicial object. Despite claims in the literature to the contrary, we show that all three are distinct concepts with strong extra degeneracy...