Ltac clean:=try (simpl;congruence).Inductive form:Set:=
  Atom : positive -> form
| Arrow : form -> form -> form
| Bot
| Conjunct : form -> form -> form
| Disjunct : form -> form -> form.Inductive form:Set:=
  Atom : positive -> form
| Arrow : form -> form -> form
| Bot
| Conjunct : form -> form -> form
| Disjunct : form -> form -> form.Inductive form:Set:=
  Atom : positive -> form
| Arrow : form -> form -> form
| Bot
| Conjunct : form -> form -> form
| Disjunct : form -> form -> form.Inductive form:Set:=
  Atom : positive -> form
| Arrow : form -> form -> form
| Bot
| Conjunct : form -> form -> form
| Disjunct : form -> form -> form.Inductive form:Set:=
  Atom : positive -> form
| Arrow : form -> form -> form
| Bot
| Conjunct : form -> form -> form
| Disjunct : form -> form -> form.Inductive form:Set:=
  Atom : positive -> form
| Arrow : form -> form -> form
| Bot
| Conjunct : form -> form -> form
| Disjunct : form -> form -> form.Notation "[ n ]":=(Atom n).Notation "A =>> B":= (Arrow A B) (at level 59, right associativity).Notation "#" := Bot.Notation "A //\\ B" := (Conjunct A B) (at level 57, left associativity).Notation "A \\// B" := (Disjunct A B) (at level 58, left associativity).Definition ctx := Store form.Fixpoint pos_eq (m n:positive) {struct m} :bool :=
match m with
  xI mm => match n with xI nn => pos_eq mm nn | _ => false end
| xO mm => match n with xO nn => pos_eq mm nn | _ => false end
| xH => match n with xH => true | _ => false end
end.

Theorem pos_eq_refl : forall m n, pos_eq m n = true -> m = n.