What is the purpose of "swap space" or "page file" in

Statements : Z < S < W < D; E ≤ C ≤ Y < D; U < T < S ≤ V

Conclusions :

I. V > Z

II. C < U

III. V > E

Statements: H ≥ D = R > I < M > U > P ≤ N

Conclusion I: H > R

II: P < M

Statements: Q ≥ R > U; R ≤ S; U ≥ B

Conclusions: I. B < R II. B ≤ Q

Statements: B % L, L & Y, Y @ I, I # Q

Conclusions: I. Q & Y                       II. B # I

Statements: W ≤ T = R; T < U < S; X = W ≥ Y

Conclusions:

I. S > Y

II. W ≥ S

III. U ≥ Y

Statements:O < P,P < Q,Q < R

Conclusions: I. P < R II. P > Q

Statements: A ≥ B > C ≥ D < E < F < G

Conclusions: I.    A > D                       II. G > C

In which of these expression ‘O ≤ F’ is definitely true?