Exercise 3-10

The free category \(3 := \mathbf{Free}(\boxed{\overset{v_1}\bullet \xrightarrow{f_1}\overset{v_2}{\bullet}\xrightarrow{f_2}\overset{v_3}{\bullet}})\) has three objects and six morphisms. Give the morphisms names and write out the composition operation in a 6x6 matrix. Which are the identities?

Solution(1)

Identities are 1,2,3

\(\circ\) 1 2 3 f1 f2 f12
1 1 f1 f12
2 2 f2
3 3
f1 f1 f12
f2 f2
f12 f12