Biconditional Introduction
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Proof Rule
The rule of biconditional introduction is a valid argument in types of logic dealing with conditionals $\implies$ and biconditionals $\iff$.
This includes classical propositional logic and predicate logic, and in particular natural deduction.
Proof Rule
- If we can conclude both $\phi \implies \psi$ and $\psi \implies \phi$, then we may infer $\phi \iff \psi$.
Sequent Form
- $p \implies q, q \implies p \vdash p \iff q$
Also known as
Some sources refer to the Biconditional Introduction as the rule of Conditional-Biconditional.