English
Fractional ideals form a cancellative commutative monoid with zero.
Русский
Дробные идеалы образуют коммутативный моноид с нулём, в котором умножение сохраняет отмену.
LaTeX
$$$$\\text{CancelCommMonoidWithZero}(\\text{FractionalIdeal}(A^0 K)).$$$$
Lean4
/-- Fractional ideals have cancellative multiplication in a Dedekind domain.
Although this instance is a direct consequence of the instance
`FractionalIdeal.semifield`, we define this instance to provide
a computable alternative.
-/
instance cancelCommMonoidWithZero : CancelCommMonoidWithZero (FractionalIdeal A⁰ K)
where
__ : CommSemiring (FractionalIdeal A⁰ K) := inferInstance
mul_left_cancel_of_ne_zero h _ _ := mul_left_cancel₀ h