theorem Th10:
  a <= b implies the carrier of Closed-Interval-MSpace(a,b) = [. a ,b .]
proof
  assume
A1: a <= b;
  then reconsider P = [. a,b .] as non empty Subset of RealSpace by XXREAL_1:1;
  thus the carrier of Closed-Interval-MSpace(a,b) = the carrier of RealSpace |
  P by A1,Def3
    .= [. a,b .] by Def2;
end;
