Metamath Proof Explorer


Theorem dmmp

Description: Domain of multiplication on positive reals. (Contributed by NM, 18-Nov-1995) (New usage is discouraged.)

Ref Expression
Assertion dmmp ⊢ dom ⁡ ⋅ 𝑷 = 𝑷 × 𝑷

Proof

Step Hyp Ref Expression
1 df-mp ⊢ ⋅ 𝑷 = x ∈ 𝑷 , y ∈ 𝑷 ⟼ z | ∃ u ∈ x ∃ v ∈ y z = u ⋅ 𝑸 v
2 mulclnq ⊢ u ∈ 𝑸 ∧ v ∈ 𝑸 → u ⋅ 𝑸 v ∈ 𝑸
3 1 2 genpdm ⊢ dom ⁡ ⋅ 𝑷 = 𝑷 × 𝑷