Set: pp::colors
  Set: pp::unicode
Notation 10 if _ then _ : implies
if ⊤ then ⊥
if ⊤ then (if a then ⊥)
implies ⊤ (implies a ⊥)
Notation 100 _ |- _ ; _ : f
f c d e
c |- d ; e
(c !) !
fact (fact c)
[ c ; d ]
[ c ; ([ d ; e ]) ]
g c (g d e)
Notation 40 _ << _ end : h
d << e end
[ c ; d << e end ]
g c (h d e)
c ** d ++ e ** c
p1 ∨ p2 ∧ p3
r (s c d) (s e c)
or p1 (and p2 p3)
c = d ∨ d = c
¬ p1 ∨ p2
p1 ∧ p3 ∨ p2 ∧ p3
or (not p1) p2
or (and p1 p3) (and p2 p3)