let A be non trivial set ; for B, Bo1 being set
for yo1 being Function of Bo1,A
for Bo2 being set
for yo2 being Function of Bo2,A st Bo1 c= B & Bo2 c= B & cylinder0 (A,B,Bo1,yo1) = cylinder0 (A,B,Bo2,yo2) holds
( Bo1 = Bo2 & yo1 = yo2 )
let B, Bo1 be set ; for yo1 being Function of Bo1,A
for Bo2 being set
for yo2 being Function of Bo2,A st Bo1 c= B & Bo2 c= B & cylinder0 (A,B,Bo1,yo1) = cylinder0 (A,B,Bo2,yo2) holds
( Bo1 = Bo2 & yo1 = yo2 )
let yo1 be Function of Bo1,A; for Bo2 being set
for yo2 being Function of Bo2,A st Bo1 c= B & Bo2 c= B & cylinder0 (A,B,Bo1,yo1) = cylinder0 (A,B,Bo2,yo2) holds
( Bo1 = Bo2 & yo1 = yo2 )
let Bo2 be set ; for yo2 being Function of Bo2,A st Bo1 c= B & Bo2 c= B & cylinder0 (A,B,Bo1,yo1) = cylinder0 (A,B,Bo2,yo2) holds
( Bo1 = Bo2 & yo1 = yo2 )
let yo2 be Function of Bo2,A; ( Bo1 c= B & Bo2 c= B & cylinder0 (A,B,Bo1,yo1) = cylinder0 (A,B,Bo2,yo2) implies ( Bo1 = Bo2 & yo1 = yo2 ) )
assume that
A1:
Bo1 c= B
and
A2:
Bo2 c= B
and
A3:
cylinder0 (A,B,Bo1,yo1) = cylinder0 (A,B,Bo2,yo2)
; ( Bo1 = Bo2 & yo1 = yo2 )
A4:
{ y where y is Function of B,A : y | Bo1 = yo1 } = cylinder0 (A,B,Bo1,yo1)
by A1, Def1;
then consider y0 being object such that
A5:
y0 in { y where y is Function of B,A : y | Bo1 = yo1 }
by XBOOLE_0:def 1;
A6:
ex y being Function of B,A st
( y0 = y & y | Bo1 = yo1 )
by A5;
A7:
{ y where y is Function of B,A : y | Bo2 = yo2 } = cylinder0 (A,B,Bo2,yo2)
by A2, Def1;
hence
Bo1 = Bo2
by A1, A2, A3, A4, Lm4; yo1 = yo2
ex w being Function of B,A st
( y0 = w & w | Bo2 = yo2 )
by A3, A4, A7, A5;
hence
yo1 = yo2
by A1, A2, A3, A4, A7, A6, Lm4; verum