It is only a monoid for non-negative numbers.
idt <*> GCD (-2) = GCD 2Thus, use this Monoid only for non-negative numbers!
:: a typeCtrl KGHC 9.10.3 · lts/ghc-9.10.x · c74966e · 2026-09-27
Modulenumeric-prelude-0.4.4Haskell98
It is only a monoid for non-negative numbers.
idt <*> GCD (-2) = GCD 2Thus, use this Monoid only for non-negative numbers!