Description: Version of rspcedvd where the implicit substitution hypothesis does not have an antecedent, which also avoids a disjoint variable condition on ph , x . (Contributed by SN, 20-Aug-2024)
|- ( x = A -> ( ps <-> ch ) )
|- ( ph -> A e. B )
|- ( ph -> ch )
|- ( ph -> E. x e. B ps )
|- ( ( A e. B /\ ch ) -> E. x e. B ps )