set P = Positives Q;
A: now :: thesis: for x being object st x in the carrier of R holds
x in (Positives Q) \/ (- (Positives Q))
let x be object ; :: thesis: ( x in the carrier of R implies b1 in (Positives Q) \/ (- (Positives Q)) )
assume x in the carrier of R ; :: thesis: b1 in (Positives Q) \/ (- (Positives Q))
then reconsider a = x as Element of R ;
per cases ( 0. R <=_ Q,a or a <=_ Q, 0. R ) by Rtot, RELAT_2:def 7;
end;
end;
for x being object st x in (Positives Q) \/ (- (Positives Q)) holds
x in the carrier of R ;
hence Positives Q is spanning by A, TARSKI:2; :: thesis: verum