let Omega, Omega2 be non empty set ; for F being SigmaField of Omega
for F2 being SigmaField of Omega2
for k being Element of set_of_random_variables_on (F,F2) holds Change_Element_to_Func (F,F2,k) is random_variable of F,F2
let F be SigmaField of Omega; for F2 being SigmaField of Omega2
for k being Element of set_of_random_variables_on (F,F2) holds Change_Element_to_Func (F,F2,k) is random_variable of F,F2
let F2 be SigmaField of Omega2; for k being Element of set_of_random_variables_on (F,F2) holds Change_Element_to_Func (F,F2,k) is random_variable of F,F2
let k be Element of set_of_random_variables_on (F,F2); Change_Element_to_Func (F,F2,k) is random_variable of F,F2
Change_Element_to_Func (F,F2,k) is Element of { f where f is Function of Omega,Omega2 : f is F,F2 -random_variable-like }
by FINANCE1:def 7;
then
Change_Element_to_Func (F,F2,k) in { f where f is Function of Omega,Omega2 : f is F,F2 -random_variable-like }
;
then
ex Y being Function of Omega,Omega2 st
( Change_Element_to_Func (F,F2,k) = Y & Y is F,F2 -random_variable-like )
;
hence
Change_Element_to_Func (F,F2,k) is random_variable of F,F2
; verum