this is a graph theory problem, please help

Toy example to demonstrate There would be no loss if we switched {(Q1,5),(23.52) TO {(Qy, )}. (az, s) In the context of stable matchings, the former will be "pareto efficient" and the same would occur if we cared about school preference . But at the same time, the latter also respects priorities in a sense 1 S3 S2 S4 a7 a8 S1 S2 2 a4 a5 a7 S1 S3 S4 1 S2 a7 2 Si (qst = 2) 1 S2 (9s2 = 2) a5 S3 (gs = 3) | as 1 S4 (gs = 1) S2 This one is a bit more involved S3 S4 S1 S1 2 S4 S2 a4 a7 S3 a4 2 a5 2 a4 a5 a7 1 S1 S3 S4 S4 S3 Si S2 S3 S2 S3 S1 S4 a8 S1 S4 S2 Toy example to demonstrate There would be no loss if we switched {(Q1,5),(23.52) TO {(Qy, )}. (az, s) In the context of stable matchings, the former will be "pareto efficient" and the same would occur if we cared about school preference . But at the same time, the latter also respects priorities in a sense 1 S3 S2 S4 a7 a8 S1 S2 2 a4 a5 a7 S1 S3 S4 1 S2 a7 2 Si (qst = 2) 1 S2 (9s2 = 2) a5 S3 (gs = 3) | as 1 S4 (gs = 1) S2 This one is a bit more involved S3 S4 S1 S1 2 S4 S2 a4 a7 S3 a4 2 a5 2 a4 a5 a7 1 S1 S3 S4 S4 S3 Si S2 S3 S2 S3 S1 S4 a8 S1 S4 S2