English
Construct a preordering from the same minimal axiom scheme for RingPreordering mk'.
Русский
Построить предпорядок по той же минимальной системе аксиом RingPreordering mk'.
LaTeX
$$Definition mk' as RingPreordering R with prescribed axioms$$
Lean4
/-- Construct a preordering from a minimal set of axioms. -/
def mk' {R : Type*} [CommRing R] (P : Set R) (add : ∀ {x y : R}, x ∈ P → y ∈ P → x + y ∈ P)
(mul : ∀ {x y : R}, x ∈ P → y ∈ P → x * y ∈ P) (sq : ∀ x : R, x * x ∈ P) (neg_one : -1 ∉ P) : RingPreordering R
where
carrier := P
add_mem' {x y} := by simpa using add
mul_mem' {x y} := by simpa using mul
zero_mem' := by simpa using sq 0
one_mem' := by simpa using sq 1