Metamath Proof Explorer


Theorem lmbr2

Description: Express the binary relation "sequence F converges to point P " in a metric space using an arbitrary upper set of integers. (Contributed by Mario Carneiro, 14-Nov-2013)

Ref Expression
Hypotheses lmbr.2 ( 𝜑𝐽 ∈ ( TopOn ‘ 𝑋 ) )
lmbr2.4 𝑍 = ( ℤ𝑀 )
lmbr2.5 ( 𝜑𝑀 ∈ ℤ )
Assertion lmbr2 ( 𝜑 → ( 𝐹 ( ⇝𝑡𝐽 ) 𝑃 ↔ ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ∧ ∀ 𝑢𝐽 ( 𝑃𝑢 → ∃ 𝑗𝑍𝑘 ∈ ( ℤ𝑗 ) ( 𝑘 ∈ dom 𝐹 ∧ ( 𝐹𝑘 ) ∈ 𝑢 ) ) ) ) )

Proof

Step Hyp Ref Expression
1 lmbr.2 ( 𝜑𝐽 ∈ ( TopOn ‘ 𝑋 ) )
2 lmbr2.4 𝑍 = ( ℤ𝑀 )
3 lmbr2.5 ( 𝜑𝑀 ∈ ℤ )
4 1 lmbr ( 𝜑 → ( 𝐹 ( ⇝𝑡𝐽 ) 𝑃 ↔ ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ∧ ∀ 𝑢𝐽 ( 𝑃𝑢 → ∃ 𝑧 ∈ ran ℤ ( 𝐹𝑧 ) : 𝑧𝑢 ) ) ) )
5 uzf : ℤ ⟶ 𝒫 ℤ
6 ffn ( ℤ : ℤ ⟶ 𝒫 ℤ → ℤ Fn ℤ )
7 reseq2 ( 𝑧 = ( ℤ𝑗 ) → ( 𝐹𝑧 ) = ( 𝐹 ↾ ( ℤ𝑗 ) ) )
8 id ( 𝑧 = ( ℤ𝑗 ) → 𝑧 = ( ℤ𝑗 ) )
9 7 8 feq12d ( 𝑧 = ( ℤ𝑗 ) → ( ( 𝐹𝑧 ) : 𝑧𝑢 ↔ ( 𝐹 ↾ ( ℤ𝑗 ) ) : ( ℤ𝑗 ) ⟶ 𝑢 ) )
10 9 rexrn ( ℤ Fn ℤ → ( ∃ 𝑧 ∈ ran ℤ ( 𝐹𝑧 ) : 𝑧𝑢 ↔ ∃ 𝑗 ∈ ℤ ( 𝐹 ↾ ( ℤ𝑗 ) ) : ( ℤ𝑗 ) ⟶ 𝑢 ) )
11 5 6 10 mp2b ( ∃ 𝑧 ∈ ran ℤ ( 𝐹𝑧 ) : 𝑧𝑢 ↔ ∃ 𝑗 ∈ ℤ ( 𝐹 ↾ ( ℤ𝑗 ) ) : ( ℤ𝑗 ) ⟶ 𝑢 )
12 pmfun ( 𝐹 ∈ ( 𝑋pm ℂ ) → Fun 𝐹 )
13 12 ad2antrl ( ( 𝜑 ∧ ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ) ) → Fun 𝐹 )
14 ffvresb ( Fun 𝐹 → ( ( 𝐹 ↾ ( ℤ𝑗 ) ) : ( ℤ𝑗 ) ⟶ 𝑢 ↔ ∀ 𝑘 ∈ ( ℤ𝑗 ) ( 𝑘 ∈ dom 𝐹 ∧ ( 𝐹𝑘 ) ∈ 𝑢 ) ) )
15 13 14 syl ( ( 𝜑 ∧ ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ) ) → ( ( 𝐹 ↾ ( ℤ𝑗 ) ) : ( ℤ𝑗 ) ⟶ 𝑢 ↔ ∀ 𝑘 ∈ ( ℤ𝑗 ) ( 𝑘 ∈ dom 𝐹 ∧ ( 𝐹𝑘 ) ∈ 𝑢 ) ) )
16 15 rexbidv ( ( 𝜑 ∧ ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ) ) → ( ∃ 𝑗 ∈ ℤ ( 𝐹 ↾ ( ℤ𝑗 ) ) : ( ℤ𝑗 ) ⟶ 𝑢 ↔ ∃ 𝑗 ∈ ℤ ∀ 𝑘 ∈ ( ℤ𝑗 ) ( 𝑘 ∈ dom 𝐹 ∧ ( 𝐹𝑘 ) ∈ 𝑢 ) ) )
17 3 adantr ( ( 𝜑 ∧ ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ) ) → 𝑀 ∈ ℤ )
18 2 rexuz3 ( 𝑀 ∈ ℤ → ( ∃ 𝑗𝑍𝑘 ∈ ( ℤ𝑗 ) ( 𝑘 ∈ dom 𝐹 ∧ ( 𝐹𝑘 ) ∈ 𝑢 ) ↔ ∃ 𝑗 ∈ ℤ ∀ 𝑘 ∈ ( ℤ𝑗 ) ( 𝑘 ∈ dom 𝐹 ∧ ( 𝐹𝑘 ) ∈ 𝑢 ) ) )
19 17 18 syl ( ( 𝜑 ∧ ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ) ) → ( ∃ 𝑗𝑍𝑘 ∈ ( ℤ𝑗 ) ( 𝑘 ∈ dom 𝐹 ∧ ( 𝐹𝑘 ) ∈ 𝑢 ) ↔ ∃ 𝑗 ∈ ℤ ∀ 𝑘 ∈ ( ℤ𝑗 ) ( 𝑘 ∈ dom 𝐹 ∧ ( 𝐹𝑘 ) ∈ 𝑢 ) ) )
20 16 19 bitr4d ( ( 𝜑 ∧ ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ) ) → ( ∃ 𝑗 ∈ ℤ ( 𝐹 ↾ ( ℤ𝑗 ) ) : ( ℤ𝑗 ) ⟶ 𝑢 ↔ ∃ 𝑗𝑍𝑘 ∈ ( ℤ𝑗 ) ( 𝑘 ∈ dom 𝐹 ∧ ( 𝐹𝑘 ) ∈ 𝑢 ) ) )
21 11 20 syl5bb ( ( 𝜑 ∧ ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ) ) → ( ∃ 𝑧 ∈ ran ℤ ( 𝐹𝑧 ) : 𝑧𝑢 ↔ ∃ 𝑗𝑍𝑘 ∈ ( ℤ𝑗 ) ( 𝑘 ∈ dom 𝐹 ∧ ( 𝐹𝑘 ) ∈ 𝑢 ) ) )
22 21 imbi2d ( ( 𝜑 ∧ ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ) ) → ( ( 𝑃𝑢 → ∃ 𝑧 ∈ ran ℤ ( 𝐹𝑧 ) : 𝑧𝑢 ) ↔ ( 𝑃𝑢 → ∃ 𝑗𝑍𝑘 ∈ ( ℤ𝑗 ) ( 𝑘 ∈ dom 𝐹 ∧ ( 𝐹𝑘 ) ∈ 𝑢 ) ) ) )
23 22 ralbidv ( ( 𝜑 ∧ ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ) ) → ( ∀ 𝑢𝐽 ( 𝑃𝑢 → ∃ 𝑧 ∈ ran ℤ ( 𝐹𝑧 ) : 𝑧𝑢 ) ↔ ∀ 𝑢𝐽 ( 𝑃𝑢 → ∃ 𝑗𝑍𝑘 ∈ ( ℤ𝑗 ) ( 𝑘 ∈ dom 𝐹 ∧ ( 𝐹𝑘 ) ∈ 𝑢 ) ) ) )
24 23 pm5.32da ( 𝜑 → ( ( ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ) ∧ ∀ 𝑢𝐽 ( 𝑃𝑢 → ∃ 𝑧 ∈ ran ℤ ( 𝐹𝑧 ) : 𝑧𝑢 ) ) ↔ ( ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ) ∧ ∀ 𝑢𝐽 ( 𝑃𝑢 → ∃ 𝑗𝑍𝑘 ∈ ( ℤ𝑗 ) ( 𝑘 ∈ dom 𝐹 ∧ ( 𝐹𝑘 ) ∈ 𝑢 ) ) ) ) )
25 df-3an ( ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ∧ ∀ 𝑢𝐽 ( 𝑃𝑢 → ∃ 𝑧 ∈ ran ℤ ( 𝐹𝑧 ) : 𝑧𝑢 ) ) ↔ ( ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ) ∧ ∀ 𝑢𝐽 ( 𝑃𝑢 → ∃ 𝑧 ∈ ran ℤ ( 𝐹𝑧 ) : 𝑧𝑢 ) ) )
26 df-3an ( ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ∧ ∀ 𝑢𝐽 ( 𝑃𝑢 → ∃ 𝑗𝑍𝑘 ∈ ( ℤ𝑗 ) ( 𝑘 ∈ dom 𝐹 ∧ ( 𝐹𝑘 ) ∈ 𝑢 ) ) ) ↔ ( ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ) ∧ ∀ 𝑢𝐽 ( 𝑃𝑢 → ∃ 𝑗𝑍𝑘 ∈ ( ℤ𝑗 ) ( 𝑘 ∈ dom 𝐹 ∧ ( 𝐹𝑘 ) ∈ 𝑢 ) ) ) )
27 24 25 26 3bitr4g ( 𝜑 → ( ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ∧ ∀ 𝑢𝐽 ( 𝑃𝑢 → ∃ 𝑧 ∈ ran ℤ ( 𝐹𝑧 ) : 𝑧𝑢 ) ) ↔ ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ∧ ∀ 𝑢𝐽 ( 𝑃𝑢 → ∃ 𝑗𝑍𝑘 ∈ ( ℤ𝑗 ) ( 𝑘 ∈ dom 𝐹 ∧ ( 𝐹𝑘 ) ∈ 𝑢 ) ) ) ) )
28 4 27 bitrd ( 𝜑 → ( 𝐹 ( ⇝𝑡𝐽 ) 𝑃 ↔ ( 𝐹 ∈ ( 𝑋pm ℂ ) ∧ 𝑃𝑋 ∧ ∀ 𝑢𝐽 ( 𝑃𝑢 → ∃ 𝑗𝑍𝑘 ∈ ( ℤ𝑗 ) ( 𝑘 ∈ dom 𝐹 ∧ ( 𝐹𝑘 ) ∈ 𝑢 ) ) ) ) )