Biconditional is Reflexive/Proof 1

Theorem

$\vdash p \iff p$

Proof

By the tableau method of natural deduction:

$\vdash p \iff p$

Line		Pool	Formula	Rule	Depends upon	Notes
1			$p \implies p$	Theorem Introduction	(None)	Law of Identity: Formulation 2
2			$p \iff p$	Biconditional Introduction: $\iff \II$	1, 1

$\blacksquare$