n (context|category theory) Given two objects
X1 and
X2, their
'product' is an object
X1 ×
X2, with projections π
1 :
X1 ×
X2 →
X1 and π
2 :
X1 ×
X2 →
X2, which satisfies the following
universal property: for any object
Y with
morphisms
f1 :
Y →
X1 and
f2 :
Y →
X2, there can naturally be constructed a unique morphism
f :
Y →
X1 ×
X2 such that
and
.