let X1, X2 be non empty set ; :: thesis: for S1 being SigmaField of X1
for S2 being SigmaField of X2
for M2 being sigma_Measure of S2
for E being Element of sigma (measurable_rectangles (S1,S2)) st E in Field_generated_by (measurable_rectangles (S1,S2)) holds
for B being Element of S2 holds E in { E where E is Element of sigma (measurable_rectangles (S1,S2)) : ex F being Function of X1,ExtREAL st
( ( for x being Element of X1 holds F . x = M2 . ((Measurable-X-section (E,x)) /\ B) ) & ( for V being Element of S1 holds F is V -measurable ) ) }
let S1 be SigmaField of X1; :: thesis: for S2 being SigmaField of X2
for M2 being sigma_Measure of S2
for E being Element of sigma (measurable_rectangles (S1,S2)) st E in Field_generated_by (measurable_rectangles (S1,S2)) holds
for B being Element of S2 holds E in { E where E is Element of sigma (measurable_rectangles (S1,S2)) : ex F being Function of X1,ExtREAL st
( ( for x being Element of X1 holds F . x = M2 . ((Measurable-X-section (E,x)) /\ B) ) & ( for V being Element of S1 holds F is V -measurable ) ) }
let S2 be SigmaField of X2; :: thesis: for M2 being sigma_Measure of S2
for E being Element of sigma (measurable_rectangles (S1,S2)) st E in Field_generated_by (measurable_rectangles (S1,S2)) holds
for B being Element of S2 holds E in { E where E is Element of sigma (measurable_rectangles (S1,S2)) : ex F being Function of X1,ExtREAL st
( ( for x being Element of X1 holds F . x = M2 . ((Measurable-X-section (E,x)) /\ B) ) & ( for V being Element of S1 holds F is V -measurable ) ) }
let M2 be sigma_Measure of S2; :: thesis: for E being Element of sigma (measurable_rectangles (S1,S2)) st E in Field_generated_by (measurable_rectangles (S1,S2)) holds
for B being Element of S2 holds E in { E where E is Element of sigma (measurable_rectangles (S1,S2)) : ex F being Function of X1,ExtREAL st
( ( for x being Element of X1 holds F . x = M2 . ((Measurable-X-section (E,x)) /\ B) ) & ( for V being Element of S1 holds F is V -measurable ) ) }
let E be Element of sigma (measurable_rectangles (S1,S2)); :: thesis: ( E in Field_generated_by (measurable_rectangles (S1,S2)) implies for B being Element of S2 holds E in { E where E is Element of sigma (measurable_rectangles (S1,S2)) : ex F being Function of X1,ExtREAL st
( ( for x being Element of X1 holds F . x = M2 . ((Measurable-X-section (E,x)) /\ B) ) & ( for V being Element of S1 holds F is V -measurable ) ) } )
assume A0: E in Field_generated_by (measurable_rectangles (S1,S2)) ; :: thesis: for B being Element of S2 holds E in { E where E is Element of sigma (measurable_rectangles (S1,S2)) : ex F being Function of X1,ExtREAL st
( ( for x being Element of X1 holds F . x = M2 . ((Measurable-X-section (E,x)) /\ B) ) & ( for V being Element of S1 holds F is V -measurable ) ) }
let B be Element of S2; :: thesis: E in { E where E is Element of sigma (measurable_rectangles (S1,S2)) : ex F being Function of X1,ExtREAL st
( ( for x being Element of X1 holds F . x = M2 . ((Measurable-X-section (E,x)) /\ B) ) & ( for V being Element of S1 holds F is V -measurable ) ) }
ex F being Function of X1,ExtREAL st
( ( for x being Element of X1 holds F . x = M2 . ((Measurable-X-section (E,x)) /\ B) ) & ( for V being Element of S1 holds F is V -measurable ) ) by A0, Th76;
hence E in { E where E is Element of sigma (measurable_rectangles (S1,S2)) : ex F being Function of X1,ExtREAL st
( ( for x being Element of X1 holds F . x = M2 . ((Measurable-X-section (E,x)) /\ B) ) & ( for V being Element of S1 holds F is V -measurable ) ) } ; :: thesis: verum