English
Applying conGen twice is the same as applying it once: conGen(conGen(r)) = conGen(r).
Русский
Повторное применение conGen даёт тот же результат: conGen(conGen(r)) = conGen(r).
LaTeX
$$$conGen(conGen(r)) = conGen(r)$$$
Lean4
/-- The map sending a binary relation to the smallest congruence relation in which it is
contained is idempotent. -/
@[to_additive addConGen_idem /-- The map sending a binary relation to the smallest additive
congruence relation in which it is contained is idempotent. -/
]
theorem conGen_idem (r : M → M → Prop) : conGen (conGen r) = conGen r := by simp