Proper handling of monic and epic functions in `id` and `comp` module

[bvssvni]

Currently, it is possible to prove that every function is both monic and epic, due to the axioms:

(f : a -> b) ⋀ (f . inv(f))  =>  id{b}
(f : a -> b) ⋀ id{b}  =>  (f . inv(f))
(f : a -> b) ⋀ (inv(f) . f)  =>  id{a}
(f : a -> b) ⋀ id{a}  =>  (inv(f). f)

This should be changed to:

~(f . inv(f)) ⋀ (f : a -> b) ⋀ (f . inv(f))  =>  id{b}
~((f . inv(f))) ⋀ (f : a -> b) ⋀ id{b}  =>  (f . inv(f))
~(inv(f) . f) ⋀ (f : a -> b) ⋀ (inv(f) . f)  =>  id{a}
~(inv(f). f) ⋀ (f : a -> b) ⋀ id{a}  =>  (inv(f). f)

Here:

• ~(f . inv(f)) is the same as saying that f is epic
• ~(inv(f) . f) is the same as saying that f is monic