Idempotent elements of a group with zero #
@[implicit_reducible]
instance
IsIdempotentElem.instZeroSubtype
{M₀ : Type u_1}
[MulZeroClass M₀]
:
Zero { p : M₀ // IsIdempotentElem p }
@[simp]
@[simp]
theorem
IsIdempotentElem.iff_eq_zero_or_one
{G₀ : Type u_2}
[MonoidWithZero G₀]
[IsLeftCancelMulZero G₀]
{p : G₀}
:
IsIdempotentElem p ↔ p = 0 ∨ p = 1