+interpretation "constructive and" 'and x y = (And x y).
+
+inductive And3 (A,B,C:CProp) : CProp ≝
+ | Conj3 : A → B → C → And3 A B C.
+
+notation < "a ∧ b ∧ c" with precedence 35 for @{'and3 $a $b $c}.
+
+interpretation "constructive ternary and" 'and3 x y z = (Conj3 x y z).
+
+inductive And4 (A,B,C,D:CProp) : CProp ≝
+ | Conj4 : A → B → C → D → And4 A B C D.
+
+notation < "a ∧ b ∧ c ∧ d" with precedence 35 for @{'and4 $a $b $c $d}.
+
+interpretation "constructive quaternary and" 'and4 x y z t = (Conj4 x y z t).
+
+coinductive product (A,B:Type) : Type ≝ pair : ∀a:A.∀b:B.product A B.
+
+notation "a \times b" left associative with precedence 70 for @{'product $a $b}.
+interpretation "prod" 'product a b = (product a b).
+
+definition first : ∀A.∀P.A × P → A ≝ λA,P,s.match s with [pair x _ ⇒ x].
+definition second : ∀A.∀P.A × P → P ≝ λA,P,s.match s with [pair _ y ⇒ y].
+
+interpretation "pair pi1" 'pi1 = (first _ _).
+interpretation "pair pi2" 'pi2 = (second _ _).
+interpretation "pair pi1" 'pi1a x = (first _ _ x).
+interpretation "pair pi2" 'pi2a x = (second _ _ x).
+interpretation "pair pi1" 'pi1b x y = (first _ _ x y).
+interpretation "pair pi2" 'pi2b x y = (second _ _ x y).
+
+notation "hvbox(\langle term 19 a, break term 19 b\rangle)"
+with precedence 90 for @{ 'pair $a $b}.
+interpretation "pair" 'pair a b = (pair _ _ a b).