Description: The logical connective ‘If and Only If’ (IFF) is an expression used in logic and mathematics to denote a biconditional relationship between two propositions. This means that both propositions are true or both are false simultaneously. In more formal terms, it can be expressed as ‘A if and only if B’, which implies that A is true exactly when B is true. This connective is fundamental in propositional logic, as it establishes an equivalence between two statements, allowing one to deduce the truth of one from the other. The notation commonly used for this connective is ‘A ↔ B’, where the arrow indicates the equivalence relationship. In the realm of logic and reasoning, the concept of ‘If and Only If’ translates into conditions that must be met for a conclusion to be drawn, which is essential for decision-making and logical deduction. Understanding it is crucial for the development of mathematical and logical theories, as well as for implementing reasoning structures in various fields.