Discrete Mathematics & Logic

Which of the following is a valid propositional logic connective?

What is the number of ways to arrange 5 distinct books on a shelf?

In set theory, which operation corresponds to elements common to both sets $A$ and $B$?

The principle of mathematical induction is used to prove statements about natural numbers.

A permutation of a set considers order, while a combination does not.

In graph theory, a connected graph must have at least one cycle.