mathlib

4d3b26f8 - feat(combinatorics/simple_graph/basic): add decidable instance for adjacency of complement (#6000)

feat(combinatorics/simple_graph/basic): add decidable instance for adjacency of complement (#6000) Add instance that states that, if the adjacency relation for a simple graph is decidable, the adjacency relation for its complement is also decidable. Co-authored-by: agusakov <39916842+agusakov@users.noreply.github.com>