42 RELATIONS [CHAP. 2
2.26. (a) {( 9 , 1 ), ( 6 , 2 ), ( 3 , 3 )}; (b) (i) { 9 , 6 , 3 },
(ii){ 1 , 2 , 3 }, (iii){( 1 , 9 ), ( 2 , 6 ), ( 3 , 3 )}; (c){( 3 , 3 )}.
2.27. (a) None; (b) (2) and (3); (c) (1) and (4); (d) all
except (3).
2.28. All are true except: (e)R={( 1 , 2 )},S={( 2 , 3 )};
(f)R={( 1 , 2 )},S={( 2 , 1 )}.2.31. (b){ 1 , 4 , 9 , 16 }; (c){ 1 , 4 , 9 , 16 },{ 2 , 8 , 18 },{ 3 , 12 }.
2.32. [{ 1 , 6 , 11 },{ 2 , 7 , 12 },{ 3 , 8 , 133 },{ 4 , 9 , 14 },
{ 5 , 10 , 15 }]
2.33. (b){( 1 , 4 ), ( 2 , 5 ), ( 3 , 6 ), ( 4 , 7 ), ( 5 , 8 ), ( 6 , 9 )}.