let x be Element of F_Complex ; :: thesis: for n being Element of NAT ex f being Function of COMPLEX ,COMPLEX st
( f = FPower x,n & f is_continuous_on COMPLEX )
A1:
the carrier of F_Complex = COMPLEX
by COMPLFLD:def 1;
defpred S1[ Element of NAT ] means ex f being Function of COMPLEX ,COMPLEX st
( f = FPower x,$1 & f is_continuous_on COMPLEX );
A2:
S1[ 0 ]
A3:
for n being Element of NAT st S1[n] holds
S1[n + 1]
proof
let n be
Element of
NAT ;
:: thesis: ( S1[n] implies S1[n + 1] )
given f being
Function of
COMPLEX ,
COMPLEX such that A4:
f = FPower x,
n
and A5:
f is_continuous_on COMPLEX
;
:: thesis: S1[n + 1]
reconsider g =
FPower x,
(n + 1) as
Function of
COMPLEX ,
COMPLEX by A1;
take
g
;
:: thesis: ( g = FPower x,(n + 1) & g is_continuous_on COMPLEX )
thus
g = FPower x,
(n + 1)
;
:: thesis: g is_continuous_on COMPLEX
consider f1 being
Function of
COMPLEX ,
COMPLEX such that A6:
f1 = FPower x,
n
and A7:
FPower x,
(n + 1) = f1 (#) (id COMPLEX )
by Th70;
thus
g is_continuous_on COMPLEX
by A4, A5, A6, A7, Th63, CFCONT_1:65;
:: thesis: verum
end;
thus
for n being Element of NAT holds S1[n]
from NAT_1:sch 1(A2, A3); :: thesis: verum