fact: Fixpoint valid_ptrs i t := match t with Pts sx _ :: s => (sx < size (ptr_ctx i)) && valid_ptrs i s | Var _ :: s => valid_ptrs i s | _ => true end.
imports: mathcomp(ssreflect ssrbool ssrnat ssrfun eqtype seq) LemmaOverloading(prelude prefix perms heaps)