Metamath Proof Explorer


Definition df-bj-inftyexpitau

Description: Definition of the auxiliary function inftyexpitau parameterizing the circle at infinity CCinfty in CCbar . We use coupling with { R. } to simplify the proof of bj-inftyexpitaudisj . (Contributed by BJ, 22-Jan-2023) The precise definition is irrelevant and should generally not be used. TODO: prove only the necessary lemmas to prove |- ( A e. RR /\ B e. RR ) -> ( ( inftyexpitauA ) = ( inftyexpitauB ) <-> ( A - B ) e. ZZ ) ) . (New usage is discouraged.)

Ref Expression
Assertion df-bj-inftyexpitau +∞e = ( 𝑥 ∈ ℝ ↦ ⟨ ( {R ‘ ( 1st𝑥 ) ) , { R } ⟩ )

Detailed syntax breakdown

Step Hyp Ref Expression
0 cinftyexpitau +∞e
1 vx 𝑥
2 cr
3 cfractemp {R
4 c1st 1st
5 1 cv 𝑥
6 5 4 cfv ( 1st𝑥 )
7 6 3 cfv ( {R ‘ ( 1st𝑥 ) )
8 cnr R
9 8 csn { R }
10 7 9 cop ⟨ ( {R ‘ ( 1st𝑥 ) ) , { R } ⟩
11 1 2 10 cmpt ( 𝑥 ∈ ℝ ↦ ⟨ ( {R ‘ ( 1st𝑥 ) ) , { R } ⟩ )
12 0 11 wceq +∞e = ( 𝑥 ∈ ℝ ↦ ⟨ ( {R ‘ ( 1st𝑥 ) ) , { R } ⟩ )