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Metamath Proof Explorer

Theorem iscnp

Description: The predicate "the class F is a continuous function from topology J to topology K at point P ". Based on Theorem 7.2(g) of Munkres p. 107. (Contributed by NM, 17-Oct-2006) (Revised by Mario Carneiro, 21-Aug-2015)

Ref Expression
Assertion iscnp ( ( 𝐽 ∈ ( TopOn ‘ 𝑋 ) ∧ 𝐾 ∈ ( TopOn ‘ 𝑌 ) ∧ 𝑃 ∈ 𝑋 ) → ( 𝐹 ∈ ( ( 𝐽 CnP 𝐾 ) ‘ 𝑃 ) ↔ ( 𝐹 : 𝑋 ⟶ 𝑌 ∧ ∀ 𝑦 ∈ 𝐾 ( ( 𝐹 ‘ 𝑃 ) ∈ 𝑦 → ∃ 𝑥 ∈ 𝐽 ( 𝑃 ∈ 𝑥 ∧ ( 𝐹 “ 𝑥 ) ⊆ 𝑦 ) ) ) ) )

Proof

Step Hyp Ref Expression
1 cnpval ⊢ ( ( 𝐽 ∈ ( TopOn ‘ 𝑋 ) ∧ 𝐾 ∈ ( TopOn ‘ 𝑌 ) ∧ 𝑃 ∈ 𝑋 ) → ( ( 𝐽 CnP 𝐾 ) ‘ 𝑃 ) = { 𝑓 ∈ ( 𝑌 ↑m 𝑋 ) ∣ ∀ 𝑦 ∈ 𝐾 ( ( 𝑓 ‘ 𝑃 ) ∈ 𝑦 → ∃ 𝑥 ∈ 𝐽 ( 𝑃 ∈ 𝑥 ∧ ( 𝑓 “ 𝑥 ) ⊆ 𝑦 ) ) } )
2 1 eleq2d ⊢ ( ( 𝐽 ∈ ( TopOn ‘ 𝑋 ) ∧ 𝐾 ∈ ( TopOn ‘ 𝑌 ) ∧ 𝑃 ∈ 𝑋 ) → ( 𝐹 ∈ ( ( 𝐽 CnP 𝐾 ) ‘ 𝑃 ) ↔ 𝐹 ∈ { 𝑓 ∈ ( 𝑌 ↑m 𝑋 ) ∣ ∀ 𝑦 ∈ 𝐾 ( ( 𝑓 ‘ 𝑃 ) ∈ 𝑦 → ∃ 𝑥 ∈ 𝐽 ( 𝑃 ∈ 𝑥 ∧ ( 𝑓 “ 𝑥 ) ⊆ 𝑦 ) ) } ) )
3 fveq1 ⊢ ( 𝑓 = 𝐹 → ( 𝑓 ‘ 𝑃 ) = ( 𝐹 ‘ 𝑃 ) )
4 3 eleq1d ⊢ ( 𝑓 = 𝐹 → ( ( 𝑓 ‘ 𝑃 ) ∈ 𝑦 ↔ ( 𝐹 ‘ 𝑃 ) ∈ 𝑦 ) )
5 imaeq1 ⊢ ( 𝑓 = 𝐹 → ( 𝑓 “ 𝑥 ) = ( 𝐹 “ 𝑥 ) )
6 5 sseq1d ⊢ ( 𝑓 = 𝐹 → ( ( 𝑓 “ 𝑥 ) ⊆ 𝑦 ↔ ( 𝐹 “ 𝑥 ) ⊆ 𝑦 ) )
7 6 anbi2d ⊢ ( 𝑓 = 𝐹 → ( ( 𝑃 ∈ 𝑥 ∧ ( 𝑓 “ 𝑥 ) ⊆ 𝑦 ) ↔ ( 𝑃 ∈ 𝑥 ∧ ( 𝐹 “ 𝑥 ) ⊆ 𝑦 ) ) )
8 7 rexbidv ⊢ ( 𝑓 = 𝐹 → ( ∃ 𝑥 ∈ 𝐽 ( 𝑃 ∈ 𝑥 ∧ ( 𝑓 “ 𝑥 ) ⊆ 𝑦 ) ↔ ∃ 𝑥 ∈ 𝐽 ( 𝑃 ∈ 𝑥 ∧ ( 𝐹 “ 𝑥 ) ⊆ 𝑦 ) ) )
9 4 8 imbi12d ⊢ ( 𝑓 = 𝐹 → ( ( ( 𝑓 ‘ 𝑃 ) ∈ 𝑦 → ∃ 𝑥 ∈ 𝐽 ( 𝑃 ∈ 𝑥 ∧ ( 𝑓 “ 𝑥 ) ⊆ 𝑦 ) ) ↔ ( ( 𝐹 ‘ 𝑃 ) ∈ 𝑦 → ∃ 𝑥 ∈ 𝐽 ( 𝑃 ∈ 𝑥 ∧ ( 𝐹 “ 𝑥 ) ⊆ 𝑦 ) ) ) )
10 9 ralbidv ⊢ ( 𝑓 = 𝐹 → ( ∀ 𝑦 ∈ 𝐾 ( ( 𝑓 ‘ 𝑃 ) ∈ 𝑦 → ∃ 𝑥 ∈ 𝐽 ( 𝑃 ∈ 𝑥 ∧ ( 𝑓 “ 𝑥 ) ⊆ 𝑦 ) ) ↔ ∀ 𝑦 ∈ 𝐾 ( ( 𝐹 ‘ 𝑃 ) ∈ 𝑦 → ∃ 𝑥 ∈ 𝐽 ( 𝑃 ∈ 𝑥 ∧ ( 𝐹 “ 𝑥 ) ⊆ 𝑦 ) ) ) )
11 10 elrab ⊢ ( 𝐹 ∈ { 𝑓 ∈ ( 𝑌 ↑m 𝑋 ) ∣ ∀ 𝑦 ∈ 𝐾 ( ( 𝑓 ‘ 𝑃 ) ∈ 𝑦 → ∃ 𝑥 ∈ 𝐽 ( 𝑃 ∈ 𝑥 ∧ ( 𝑓 “ 𝑥 ) ⊆ 𝑦 ) ) } ↔ ( 𝐹 ∈ ( 𝑌 ↑m 𝑋 ) ∧ ∀ 𝑦 ∈ 𝐾 ( ( 𝐹 ‘ 𝑃 ) ∈ 𝑦 → ∃ 𝑥 ∈ 𝐽 ( 𝑃 ∈ 𝑥 ∧ ( 𝐹 “ 𝑥 ) ⊆ 𝑦 ) ) ) )
12 toponmax ⊢ ( 𝐾 ∈ ( TopOn ‘ 𝑌 ) → 𝑌 ∈ 𝐾 )
13 toponmax ⊢ ( 𝐽 ∈ ( TopOn ‘ 𝑋 ) → 𝑋 ∈ 𝐽 )
14 elmapg ⊢ ( ( 𝑌 ∈ 𝐾 ∧ 𝑋 ∈ 𝐽 ) → ( 𝐹 ∈ ( 𝑌 ↑m 𝑋 ) ↔ 𝐹 : 𝑋 ⟶ 𝑌 ) )
15 12 13 14 syl2anr ⊢ ( ( 𝐽 ∈ ( TopOn ‘ 𝑋 ) ∧ 𝐾 ∈ ( TopOn ‘ 𝑌 ) ) → ( 𝐹 ∈ ( 𝑌 ↑m 𝑋 ) ↔ 𝐹 : 𝑋 ⟶ 𝑌 ) )
16 15 anbi1d ⊢ ( ( 𝐽 ∈ ( TopOn ‘ 𝑋 ) ∧ 𝐾 ∈ ( TopOn ‘ 𝑌 ) ) → ( ( 𝐹 ∈ ( 𝑌 ↑m 𝑋 ) ∧ ∀ 𝑦 ∈ 𝐾 ( ( 𝐹 ‘ 𝑃 ) ∈ 𝑦 → ∃ 𝑥 ∈ 𝐽 ( 𝑃 ∈ 𝑥 ∧ ( 𝐹 “ 𝑥 ) ⊆ 𝑦 ) ) ) ↔ ( 𝐹 : 𝑋 ⟶ 𝑌 ∧ ∀ 𝑦 ∈ 𝐾 ( ( 𝐹 ‘ 𝑃 ) ∈ 𝑦 → ∃ 𝑥 ∈ 𝐽 ( 𝑃 ∈ 𝑥 ∧ ( 𝐹 “ 𝑥 ) ⊆ 𝑦 ) ) ) ) )
17 11 16 bitrid ⊢ ( ( 𝐽 ∈ ( TopOn ‘ 𝑋 ) ∧ 𝐾 ∈ ( TopOn ‘ 𝑌 ) ) → ( 𝐹 ∈ { 𝑓 ∈ ( 𝑌 ↑m 𝑋 ) ∣ ∀ 𝑦 ∈ 𝐾 ( ( 𝑓 ‘ 𝑃 ) ∈ 𝑦 → ∃ 𝑥 ∈ 𝐽 ( 𝑃 ∈ 𝑥 ∧ ( 𝑓 “ 𝑥 ) ⊆ 𝑦 ) ) } ↔ ( 𝐹 : 𝑋 ⟶ 𝑌 ∧ ∀ 𝑦 ∈ 𝐾 ( ( 𝐹 ‘ 𝑃 ) ∈ 𝑦 → ∃ 𝑥 ∈ 𝐽 ( 𝑃 ∈ 𝑥 ∧ ( 𝐹 “ 𝑥 ) ⊆ 𝑦 ) ) ) ) )
18 17 3adant3 ⊢ ( ( 𝐽 ∈ ( TopOn ‘ 𝑋 ) ∧ 𝐾 ∈ ( TopOn ‘ 𝑌 ) ∧ 𝑃 ∈ 𝑋 ) → ( 𝐹 ∈ { 𝑓 ∈ ( 𝑌 ↑m 𝑋 ) ∣ ∀ 𝑦 ∈ 𝐾 ( ( 𝑓 ‘ 𝑃 ) ∈ 𝑦 → ∃ 𝑥 ∈ 𝐽 ( 𝑃 ∈ 𝑥 ∧ ( 𝑓 “ 𝑥 ) ⊆ 𝑦 ) ) } ↔ ( 𝐹 : 𝑋 ⟶ 𝑌 ∧ ∀ 𝑦 ∈ 𝐾 ( ( 𝐹 ‘ 𝑃 ) ∈ 𝑦 → ∃ 𝑥 ∈ 𝐽 ( 𝑃 ∈ 𝑥 ∧ ( 𝐹 “ 𝑥 ) ⊆ 𝑦 ) ) ) ) )
19 2 18 bitrd ⊢ ( ( 𝐽 ∈ ( TopOn ‘ 𝑋 ) ∧ 𝐾 ∈ ( TopOn ‘ 𝑌 ) ∧ 𝑃 ∈ 𝑋 ) → ( 𝐹 ∈ ( ( 𝐽 CnP 𝐾 ) ‘ 𝑃 ) ↔ ( 𝐹 : 𝑋 ⟶ 𝑌 ∧ ∀ 𝑦 ∈ 𝐾 ( ( 𝐹 ‘ 𝑃 ) ∈ 𝑦 → ∃ 𝑥 ∈ 𝐽 ( 𝑃 ∈ 𝑥 ∧ ( 𝐹 “ 𝑥 ) ⊆ 𝑦 ) ) ) ) )