English
The map sending a congruence to its underlying Setoid is injective: if c.toSetoid = d.toSetoid then c = d.
Русский
Отображение конгруэнции к её базовой Setoid инъективно: если c.toSetoid = d.toSetoid, то c = d.
LaTeX
$$$c.toSetoid = d.toSetoid \\Rightarrow c = d$$$
Lean4
/-- The map sending a congruence relation to its underlying equivalence relation is injective. -/
@[to_additive /-- The map sending an additive congruence relation to its underlying equivalence
relation is injective. -/
]
theorem toSetoid_inj {c d : Con M} (H : c.toSetoid = d.toSetoid) : c = d :=
ext <| Setoid.ext_iff.1 H