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Metamath Proof Explorer

Theorem xpsxmet

Description: A product metric of extended metrics is an extended metric. (Contributed by Mario Carneiro, 21-Aug-2015)

Ref Expression
Hypotheses xpsds.t ⊢ 𝑇 = ( 𝑅 ×s 𝑆 )
xpsds.x ⊢ 𝑋 = ( Base ‘ 𝑅 )
xpsds.y ⊢ 𝑌 = ( Base ‘ 𝑆 )
xpsds.1 ⊢ ( 𝜑 → 𝑅 ∈ 𝑉 )
xpsds.2 ⊢ ( 𝜑 → 𝑆 ∈ 𝑊 )
xpsds.p ⊢ 𝑃 = ( dist ‘ 𝑇 )
xpsds.m ⊢ 𝑀 = ( ( dist ‘ 𝑅 ) ↾ ( 𝑋 × 𝑋 ) )
xpsds.n ⊢ 𝑁 = ( ( dist ‘ 𝑆 ) ↾ ( 𝑌 × 𝑌 ) )
xpsds.3 ⊢ ( 𝜑 → 𝑀 ∈ ( ∞Met ‘ 𝑋 ) )
xpsds.4 ⊢ ( 𝜑 → 𝑁 ∈ ( ∞Met ‘ 𝑌 ) )
Assertion xpsxmet ( 𝜑 → 𝑃 ∈ ( ∞Met ‘ ( 𝑋 × 𝑌 ) ) )

Proof

Step Hyp Ref Expression
1 xpsds.t ⊢ 𝑇 = ( 𝑅 ×s 𝑆 )
2 xpsds.x ⊢ 𝑋 = ( Base ‘ 𝑅 )
3 xpsds.y ⊢ 𝑌 = ( Base ‘ 𝑆 )
4 xpsds.1 ⊢ ( 𝜑 → 𝑅 ∈ 𝑉 )
5 xpsds.2 ⊢ ( 𝜑 → 𝑆 ∈ 𝑊 )
6 xpsds.p ⊢ 𝑃 = ( dist ‘ 𝑇 )
7 xpsds.m ⊢ 𝑀 = ( ( dist ‘ 𝑅 ) ↾ ( 𝑋 × 𝑋 ) )
8 xpsds.n ⊢ 𝑁 = ( ( dist ‘ 𝑆 ) ↾ ( 𝑌 × 𝑌 ) )
9 xpsds.3 ⊢ ( 𝜑 → 𝑀 ∈ ( ∞Met ‘ 𝑋 ) )
10 xpsds.4 ⊢ ( 𝜑 → 𝑁 ∈ ( ∞Met ‘ 𝑌 ) )
11 eqid ⊢ ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) = ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } )
12 eqid ⊢ ( Scalar ‘ 𝑅 ) = ( Scalar ‘ 𝑅 )
13 eqid ⊢ ( ( Scalar ‘ 𝑅 ) Xs { ⟨ ∅ , 𝑅 ⟩ , ⟨ 1o , 𝑆 ⟩ } ) = ( ( Scalar ‘ 𝑅 ) Xs { ⟨ ∅ , 𝑅 ⟩ , ⟨ 1o , 𝑆 ⟩ } )
14 1 2 3 4 5 11 12 13 xpsval ⊢ ( 𝜑 → 𝑇 = ( ◡ ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) “s ( ( Scalar ‘ 𝑅 ) Xs { ⟨ ∅ , 𝑅 ⟩ , ⟨ 1o , 𝑆 ⟩ } ) ) )
15 1 2 3 4 5 11 12 13 xpsrnbas ⊢ ( 𝜑 → ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) = ( Base ‘ ( ( Scalar ‘ 𝑅 ) Xs { ⟨ ∅ , 𝑅 ⟩ , ⟨ 1o , 𝑆 ⟩ } ) ) )
16 11 xpsff1o2 ⊢ ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) : ( 𝑋 × 𝑌 ) –1-1-onto→ ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } )
17 f1ocnv ⊢ ( ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) : ( 𝑋 × 𝑌 ) –1-1-onto→ ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) → ◡ ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) : ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) –1-1-onto→ ( 𝑋 × 𝑌 ) )
18 16 17 mp1i ⊢ ( 𝜑 → ◡ ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) : ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) –1-1-onto→ ( 𝑋 × 𝑌 ) )
19 ovexd ⊢ ( 𝜑 → ( ( Scalar ‘ 𝑅 ) Xs { ⟨ ∅ , 𝑅 ⟩ , ⟨ 1o , 𝑆 ⟩ } ) ∈ V )
20 eqid ⊢ ( ( dist ‘ ( ( Scalar ‘ 𝑅 ) Xs { ⟨ ∅ , 𝑅 ⟩ , ⟨ 1o , 𝑆 ⟩ } ) ) ↾ ( ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) × ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) ) ) = ( ( dist ‘ ( ( Scalar ‘ 𝑅 ) Xs { ⟨ ∅ , 𝑅 ⟩ , ⟨ 1o , 𝑆 ⟩ } ) ) ↾ ( ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) × ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) ) )
21 1 2 3 4 5 6 7 8 9 10 xpsxmetlem ⊢ ( 𝜑 → ( dist ‘ ( ( Scalar ‘ 𝑅 ) Xs { ⟨ ∅ , 𝑅 ⟩ , ⟨ 1o , 𝑆 ⟩ } ) ) ∈ ( ∞Met ‘ ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) ) )
22 ssid ⊢ ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) ⊆ ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } )
23 xmetres2 ⊢ ( ( ( dist ‘ ( ( Scalar ‘ 𝑅 ) Xs { ⟨ ∅ , 𝑅 ⟩ , ⟨ 1o , 𝑆 ⟩ } ) ) ∈ ( ∞Met ‘ ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) ) ∧ ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) ⊆ ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) ) → ( ( dist ‘ ( ( Scalar ‘ 𝑅 ) Xs { ⟨ ∅ , 𝑅 ⟩ , ⟨ 1o , 𝑆 ⟩ } ) ) ↾ ( ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) × ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) ) ) ∈ ( ∞Met ‘ ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) ) )
24 21 22 23 sylancl ⊢ ( 𝜑 → ( ( dist ‘ ( ( Scalar ‘ 𝑅 ) Xs { ⟨ ∅ , 𝑅 ⟩ , ⟨ 1o , 𝑆 ⟩ } ) ) ↾ ( ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) × ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) ) ) ∈ ( ∞Met ‘ ran ( 𝑥 ∈ 𝑋 , 𝑦 ∈ 𝑌 ↦ { ⟨ ∅ , 𝑥 ⟩ , ⟨ 1o , 𝑦 ⟩ } ) ) )
25 14 15 18 19 20 6 24 imasf1oxmet ⊢ ( 𝜑 → 𝑃 ∈ ( ∞Met ‘ ( 𝑋 × 𝑌 ) ) )