Congruence in a Category

A congruence in a Category 𝒞 𝒞 \mathcal{C} is a sort of "internal equivalence relation" to 𝒞 𝒞 \mathcal{C} . Explicitly, a congruence is a Jointly Monic Pair X ← p 1 R → p 2 X subscript 𝑝 1 ← 𝑋 𝑅 subscript 𝑝 2 → 𝑋 X\xleftarrow{p_{1}}R\xrightarrow{p_{2}}X equipped with Morphism of Spans that witness reflexivity, symmetry, and transitivity.