English
The set of nonnegative elements in an ordered semiring forms a subsemiring.
Русский
Множество неотрицательных элементов упорядоченного полукольца формирует подпол semiring.
LaTeX
$$$\\text{nonneg}(R) = \\{ x \\in R \\;|\\; 0 \\le x \\}$ defines a Subsemiring of R$$
Lean4
/-- The set of nonnegative elements in an ordered semiring, as a subsemiring. -/
@[simps]
def nonneg : Subsemiring R where
carrier := Set.Ici 0
mul_mem' := mul_nonneg
one_mem' := zero_le_one
add_mem' := add_nonneg
zero_mem' := le_rfl