Metamath Proof Explorer


Definition df-rediv

Description: Define division between real numbers. This operator saves ax-mulcom over df-div in certain situations. (Contributed by SN, 25-Nov-2025)

Ref Expression
Assertion df-rediv /ℝ = ( 𝑥 ∈ ℝ , 𝑦 ∈ ( ℝ ∖ { 0 } ) ↦ ( ℩ 𝑧 ∈ ℝ ( 𝑦 · 𝑧 ) = 𝑥 ) )

Detailed syntax breakdown

Step Hyp Ref Expression
0 crediv ⊢ /ℝ
1 vx ⊢ 𝑥
2 cr ⊢ ℝ
3 vy ⊢ 𝑦
4 cc0 ⊢ 0
5 4 csn ⊢ { 0 }
6 2 5 cdif ⊢ ( ℝ ∖ { 0 } )
7 vz ⊢ 𝑧
8 3 cv ⊢ 𝑦
9 cmul ⊢ ·
10 7 cv ⊢ 𝑧
11 8 10 9 co ⊢ ( 𝑦 · 𝑧 )
12 1 cv ⊢ 𝑥
13 11 12 wceq ⊢ ( 𝑦 · 𝑧 ) = 𝑥
14 13 7 2 crio ⊢ ( ℩ 𝑧 ∈ ℝ ( 𝑦 · 𝑧 ) = 𝑥 )
15 1 3 2 6 14 cmpo ⊢ ( 𝑥 ∈ ℝ , 𝑦 ∈ ( ℝ ∖ { 0 } ) ↦ ( ℩ 𝑧 ∈ ℝ ( 𝑦 · 𝑧 ) = 𝑥 ) )
16 0 15 wceq ⊢ /ℝ = ( 𝑥 ∈ ℝ , 𝑦 ∈ ( ℝ ∖ { 0 } ) ↦ ( ℩ 𝑧 ∈ ℝ ( 𝑦 · 𝑧 ) = 𝑥 ) )