let T be non empty TopSpace; for pmet being Function of [: the carrier of T, the carrier of T:],REAL st pmet is_a_pseudometric_of the carrier of T & ( for pmet9 being RealMap of [:T,T:] st pmet = pmet9 holds
pmet9 is continuous ) holds
for A being non empty Subset of T
for p being Point of T st p in Cl A holds
(lower_bound (pmet,A)) . p = 0
set rn = In (0,REAL);
let pmet be Function of [: the carrier of T, the carrier of T:],REAL; ( pmet is_a_pseudometric_of the carrier of T & ( for pmet9 being RealMap of [:T,T:] st pmet = pmet9 holds
pmet9 is continuous ) implies for A being non empty Subset of T
for p being Point of T st p in Cl A holds
(lower_bound (pmet,A)) . p = 0 )
assume that
A1:
pmet is_a_pseudometric_of the carrier of T
and
A2:
for pmet9 being RealMap of [:T,T:] st pmet = pmet9 holds
pmet9 is continuous
; for A being non empty Subset of T
for p being Point of T st p in Cl A holds
(lower_bound (pmet,A)) . p = 0
let A be non empty Subset of T; for p being Point of T st p in Cl A holds
(lower_bound (pmet,A)) . p = 0
let p be Point of T; ( p in Cl A implies (lower_bound (pmet,A)) . p = 0 )
A3:
dom (lower_bound (pmet,A)) = the carrier of T
by FUNCT_2:def 1;
reconsider Z = {(In (0,REAL))}, infA = (lower_bound (pmet,A)) .: A as Subset of R^1 by TOPMETR:17;
infA c= Z
then A4:
Cl infA c= Cl Z
by PRE_TOPC:19;
reconsider InfA = lower_bound (pmet,A) as Function of T,R^1 by TOPMETR:17;
for p being Point of T holds dist (pmet,p) is continuous
by A2, Th4;
then
lower_bound (pmet,A) is continuous
by A1, Th8;
then
InfA is continuous
by JORDAN5A:27;
then A5:
InfA .: (Cl A) c= Cl (InfA .: A)
by TOPS_2:45;
assume
p in Cl A
; (lower_bound (pmet,A)) . p = 0
then A6:
(lower_bound (pmet,A)) . p in (lower_bound (pmet,A)) .: (Cl A)
by A3, FUNCT_1:def 6;
Z is closed
by PCOMPS_1:7, TOPMETR:17;
then
Z = Cl Z
by PRE_TOPC:22;
then
InfA .: (Cl A) c= Z
by A4, A5;
hence
(lower_bound (pmet,A)) . p = 0
by A6, TARSKI:def 1; verum