English
For any subgroup s of α, the quotient α / s exists as a quotient type (has well-defined left cosets).
Русский
Для любой подгруппы s группы α существует фактор-группа α / s (множество левых косет).
LaTeX
$$HasQuotient α (Subgroup α)$$
Lean4
/-- `α ⧸ s` is the quotient type representing the left cosets of `s`. If `s` is a normal subgroup,
`α ⧸ s` is a group -/
@[to_additive /-- `α ⧸ s` is the quotient type representing the left cosets of `s`. If `s` is a
normal subgroup, `α ⧸ s` is a group -/
]
instance instHasQuotientSubgroup : HasQuotient α (Subgroup α) :=
⟨fun s => Quotient (leftRel s)⟩