Let $$a: \sim(p \wedge \sim r) \vee(\sim q \vee s)$$ and $$b:(p \vee s) \leftrightarrow(q \wedge r)$$.

If the truth values of $$p$$ and $$q$$ are true and that of $$r$$ and $$s$$ are false, then the truth values of $$a$$ and $$b$$ are respectively

The logical statement (p $$\to$$ q) $$\wedge$$ (q $$\to$$ ~p) is equivalent to

If p $$\to$$ (~p $$\vee$$ q) is false, then the truth values of p and q are, respectively

Negation of the statement $$\forall x \in R, x^2+1=0$$ is