Identity
Let f : A → B be a morphism of a category containing two objects A and B. Associated with these objects are the identity morphisms 1A : A → A and 1B : B → B. By composing these with f, we construct two morphisms:
- f 1A : A → B, and
- 1B f : A → B.
Both are morphisms between the same objects as f. We have, accordingly, the following coherence statement:
- f 1A = f = 1B f.
Read more about this topic: Coherence Condition
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