English
MulArchimedean on WithZero M follows from MulArchimedean on M.
Русский
MulArchimedean на WithZero M следует из MulArchimedean на M.
LaTeX
$$$$ \text{MulArchimedean}(M) \Rightarrow \text{MulArchimedean}(WithZero M). $$$$
Lean4
instance instMulArchimedean (M) [CommMonoid M] [PartialOrder M] [MulArchimedean M] : MulArchimedean (WithZero M) :=
by
constructor
intro x y hxy
cases y with
| zero => exact absurd hxy (zero_le _).not_gt
| coe y =>
cases x with
| zero => refine ⟨0, zero_le _⟩
| coe x => simpa [← WithZero.coe_pow] using (MulArchimedean.arch x (by simpa using hxy))