English
The submodule action of the decomposition subgroup on valuation subring A is well-defined and preserves A.
Русский
Подмодульное действие декомпозиционной подгруппы на оценочное подкольцо A определено и сохраняет A.
LaTeX
$$$\\text{subMulAction}(A)(g,x) \\in A$ при g в декомпозиционной подгруппе.$$
Lean4
/-- The valuation subring `A` (considered as a subset of `L`)
is stable under the action of the decomposition group. -/
def subMulAction (A : ValuationSubring L) : SubMulAction (A.decompositionSubgroup K) L
where
carrier := A
smul_mem' g _ h := Set.mem_of_mem_of_subset (Set.smul_mem_smul_set h) g.prop.le