Associated, prime, and irreducible elements. #
In this file we define the predicate Prime p
saying that an element of a commutative monoid with zero is prime.
Namely, Prime p
means that p
isn't zero, it isn't a unit,
and p ∣ a * b → p ∣ a ∨ p ∣ b
for all a
, b
;
In decomposition monoids (e.g., ℕ
, ℤ
), this predicate is equivalent to Irreducible
,
however this is not true in general.
We also define an equivalence relation Associated
saying that two elements of a monoid differ by a multiplication by a unit.
Then we show that the quotient type Associates
is a monoid
and prove basic properties of this quotient.
Equations
- Associates.instOrderedCommMonoid = OrderedCommMonoid.mk ⋯
Equations
- Associates.instCanonicallyOrderedCommMonoid = CanonicallyOrderedCommMonoid.mk ⋯ ⋯