Metamath Proof Explorer


Theorem elcnfn

Description: Property defining a continuous functional. (Contributed by NM, 11-Feb-2006) (Revised by Mario Carneiro, 16-Nov-2013) (New usage is discouraged.)

Ref Expression
Assertion elcnfn T ContFn T : x y + z + w norm w - x < z T w T x < y

Proof

Step Hyp Ref Expression
1 fveq1 t = T t w = T w
2 fveq1 t = T t x = T x
3 1 2 oveq12d t = T t w t x = T w T x
4 3 fveq2d t = T t w t x = T w T x
5 4 breq1d t = T t w t x < y T w T x < y
6 5 imbi2d t = T norm w - x < z t w t x < y norm w - x < z T w T x < y
7 6 rexralbidv t = T z + w norm w - x < z t w t x < y z + w norm w - x < z T w T x < y
8 7 2ralbidv t = T x y + z + w norm w - x < z t w t x < y x y + z + w norm w - x < z T w T x < y
9 df-cnfn ContFn = t | x y + z + w norm w - x < z t w t x < y
10 8 9 elrab2 T ContFn T x y + z + w norm w - x < z T w T x < y
11 cnex V
12 ax-hilex V
13 11 12 elmap T T :
14 13 anbi1i T x y + z + w norm w - x < z T w T x < y T : x y + z + w norm w - x < z T w T x < y
15 10 14 bitri T ContFn T : x y + z + w norm w - x < z T w T x < y