Metamath Proof Explorer


Theorem stoweidlem9

Description: Lemma for stoweid : here the Stone Weierstrass theorem is proven for the trivial case, T is the empty set. (Contributed by Glauco Siliprandi, 20-Apr-2017)

Ref Expression
Hypotheses stoweidlem9.1
|- ( ph -> T = (/) )
stoweidlem9.2
|- ( ph -> ( t e. T |-> 1 ) e. A )
Assertion stoweidlem9
|- ( ph -> E. g e. A A. t e. T ( abs ` ( ( g ` t ) - ( F ` t ) ) ) < E )

Proof

Step Hyp Ref Expression
1 stoweidlem9.1
 |-  ( ph -> T = (/) )
2 stoweidlem9.2
 |-  ( ph -> ( t e. T |-> 1 ) e. A )
3 mpteq1
 |-  ( T = (/) -> ( t e. T |-> 1 ) = ( t e. (/) |-> 1 ) )
4 mpt0
 |-  ( t e. (/) |-> 1 ) = (/)
5 3 4 eqtrdi
 |-  ( T = (/) -> ( t e. T |-> 1 ) = (/) )
6 1 5 syl
 |-  ( ph -> ( t e. T |-> 1 ) = (/) )
7 6 2 eqeltrrd
 |-  ( ph -> (/) e. A )
8 rzal
 |-  ( T = (/) -> A. t e. T ( abs ` ( ( (/) ` t ) - ( F ` t ) ) ) < E )
9 1 8 syl
 |-  ( ph -> A. t e. T ( abs ` ( ( (/) ` t ) - ( F ` t ) ) ) < E )
10 fveq1
 |-  ( g = (/) -> ( g ` t ) = ( (/) ` t ) )
11 10 fvoveq1d
 |-  ( g = (/) -> ( abs ` ( ( g ` t ) - ( F ` t ) ) ) = ( abs ` ( ( (/) ` t ) - ( F ` t ) ) ) )
12 11 breq1d
 |-  ( g = (/) -> ( ( abs ` ( ( g ` t ) - ( F ` t ) ) ) < E <-> ( abs ` ( ( (/) ` t ) - ( F ` t ) ) ) < E ) )
13 12 ralbidv
 |-  ( g = (/) -> ( A. t e. T ( abs ` ( ( g ` t ) - ( F ` t ) ) ) < E <-> A. t e. T ( abs ` ( ( (/) ` t ) - ( F ` t ) ) ) < E ) )
14 13 rspcev
 |-  ( ( (/) e. A /\ A. t e. T ( abs ` ( ( (/) ` t ) - ( F ` t ) ) ) < E ) -> E. g e. A A. t e. T ( abs ` ( ( g ` t ) - ( F ` t ) ) ) < E )
15 7 9 14 syl2anc
 |-  ( ph -> E. g e. A A. t e. T ( abs ` ( ( g ` t ) - ( F ` t ) ) ) < E )