mathlib3

aee918b8 - feat(algebraic_topology/simplicial_object): Some API for converting between simplicial and cosimplicial (#7656)

feat(algebraic_topology/simplicial_object): Some API for converting between simplicial and cosimplicial (#7656) This adds some code which is helpful to convert back and forth between simplicial and cosimplicial object. For augmented objects, this doesn't follow directly from the existing API in `category_theory/opposite`. Co-authored-by: Adam Topaz <adamtopaz@users.noreply.github.com>