sig pic.

kind  n, a, p      type.

type  eq           p -> p -> o.

type  null         p.
type  bang, taup   p -> p.
type  match, out   n -> n -> p -> p.
type  plus, par    p -> p -> p.
type  nu           (n -> p) -> p.
type  in           n -> (n -> p) -> p.

type  tau          a.
type  dn, up       n -> n -> a.

type  one          p -> a -> p -> o.
type  oneb         p -> (n -> a) -> (n -> p) -> o.
