Section Properties.
Context {A val : Type} {Heq : RelDec (@eq A)} {HeqOk : RelDec_Correct Heq}.
Context {R : ValNull val}.
Local Open Scope open_scope.

Lemma substl_trunc_notin x' xs es :
~ In x' xs ->
substl_trunc (combine xs es) x' = @empty_open _ val _.