fact: Definition case0 {A} (P:vec A 0 -> Type) (H:P (@Vector.nil A)) v:P v := match v with |vec_nil => H |_ => fun devil => False_ind (@IDProp) devil end.
imports: Arith Lia List Permutation Undecidability.Shared.Libs.DLW.Utils(utils) Undecidability.Shared.Libs.DLW.Vec(pos)