  We present ViCAR, a library for working with monoidal categories in the Coq
proof assistant. ViCAR provides definitions for categorical structures that
users can instantiate with their own verification projects. Upon verifying
relevant coherence conditions, ViCAR gives a set of lemmas and tactics for
manipulating categorical structures. We also provide a visualizer that can
display any composition and tensor product of morphisms as a string diagram,
showing its categorical structure. This enables graphical reasoning and
automated rewriting for Coq projects with monoidal structures.
