sTactic

# Library sTactic

`
Theorem Contradict1 : forall a b : Prop, b -> (a -> ~ b) -> ~ a.
Theorem Contradict2 : forall a b : Prop, b -> ~ b -> a.
Theorem Contradict3 : forall a : Prop, a -> ~ ~ a.
Ltac Contradict name :=
(apply (fun a : Prop => Contradict1 a _ name); clear name; intros name) ||
(apply (fun a : Prop => Contradict2 a _ name); clear name);
try apply Contradict3.
Ltac CaseEq name :=
generalize (refl_equal name); pattern name at -1 in |- *; case name.
Ltac Casec name := case name; clear name.
Ltac Elimc name := elim name; clear name.
`