let X be non empty set ; for S being SigmaField of X
for M being sigma_Measure of S
for f being PartFunc of X,REAL
for k being positive Real st f in Lp_Functions (M,k) holds
abs f in Lp_Functions (M,k)
let S be SigmaField of X; for M being sigma_Measure of S
for f being PartFunc of X,REAL
for k being positive Real st f in Lp_Functions (M,k) holds
abs f in Lp_Functions (M,k)
let M be sigma_Measure of S; for f being PartFunc of X,REAL
for k being positive Real st f in Lp_Functions (M,k) holds
abs f in Lp_Functions (M,k)
let f be PartFunc of X,REAL; for k being positive Real st f in Lp_Functions (M,k) holds
abs f in Lp_Functions (M,k)
let k be positive Real; ( f in Lp_Functions (M,k) implies abs f in Lp_Functions (M,k) )
set W = Lp_Functions (M,k);
assume
f in Lp_Functions (M,k)
; abs f in Lp_Functions (M,k)
then consider f1 being PartFunc of X,REAL such that
A1:
( f1 = f & ex Ef1 being Element of S st
( M . (Ef1 `) = 0 & dom f1 = Ef1 & f1 is Ef1 -measurable & (abs f1) to_power k is_integrable_on M ) )
;
consider Ef being Element of S such that
A2:
( M . (Ef `) = 0 & dom f1 = Ef & f1 is Ef -measurable & (abs f1) to_power k is_integrable_on M )
by A1;
dom (abs f1) = Ef
by A2, VALUED_1:def 11;
then Z1:
( M . (Ef `) = 0 & dom (abs f1) = Ef & abs f1 is Ef -measurable & (abs (abs f1)) to_power k is_integrable_on M )
by A2, MESFUNC6:48;
thus
abs f in Lp_Functions (M,k)
by A1, Z1; verum