Answer to Question #294608 in Discrete Mathematics for Yaku

Question

a) Prove that the set { \downarrow } is an adequate set of connectives.

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b) Consider the set

F = {y | y = ax³ + b},

a, b being constants such that a != 0 and x   \mathbb {R}.
Is F \approx \mathbb{R}? If so, prove it. If not, explain in details why it is not the case.