Functor

class discopy.feedback.Functor(ob=None, ar=None, dom=None, cod=None)

Bases: discopy.markov.Functor

A feedback functor is a markov one that preserves delay and feedback.

Parameters:

• ob (Mapping[monoidal.Ty, monoidal.Ty]) – Map from monoidal.Ty to cod.ob.

• ar (Mapping[Box, Diagram]) – Map from Box to cod.ar.

• cod (Category) – The codomain, Category(Ty, Diagram) by default.

• dom (T) –

Example

>>> x, y, m = [Ty(Ob(n, is_constant=False)) for n in "xym"]
>>> f = Box('f', x @ m.d, y @ m)
>>> g = Box('g', y.d @ m.d.d, x.d @ m.d)
>>> F = Functor({x: y.d, y: x.d, m: m.d}, {f: g})

>>> assert F(f.delay()) == F(f).delay()
>>> assert F(f.feedback()) == F(f).feedback()
>>> assert F(x.head) == F(x).head and F(x.tail) == F(x).tail
>>> assert F(FollowedBy(x)) == FollowedBy(F(x))
>>> assert F(f.head) == F(f).head and F(f.tail) == F(f).tail