Theorem xrsstr

Description: The extended real structure is a structure. (Contributed by Mario Carneiro, 21-Aug-2015)

	Ref	Expression
Assertion	xrsstr	⊢ ℝ*𝑠 Struct ⟨ 1 , ; 1 2 ⟩

Proof

Step	Hyp	Ref	Expression
1		df-xrs	⊢ ℝ*𝑠 = ( { ⟨ ( Base ‘ ndx ) , ℝ* ⟩ , ⟨ ( +g ‘ ndx ) , +e ⟩ , ⟨ ( .r ‘ ndx ) , ·e ⟩ } ∪ { ⟨ ( TopSet ‘ ndx ) , ( ordTop ‘ ≤ ) ⟩ , ⟨ ( le ‘ ndx ) , ≤ ⟩ , ⟨ ( dist ‘ ndx ) , ( 𝑥 ∈ ℝ* , 𝑦 ∈ ℝ* ↦ if ( 𝑥 ≤ 𝑦 , ( 𝑦 +e -e 𝑥 ) , ( 𝑥 +e -e 𝑦 ) ) ) ⟩ } )
2	1	odrngstr	⊢ ℝ*𝑠 Struct ⟨ 1 , ; 1 2 ⟩