R := {[x]:x > 1 };
R;
R2 := subsetof R;
R2;

R - R2;
R subset R2;
R2 - R;
R2 subset R;

S := {[x]: x > 0};
S - R; 
R subset S;
S - R2;
R2 subset S;

S2 := {[x]: x > -1};
S3 := subsetof S2;
S3 - S;
S subset S3;