Theorem hadifpOLD

Obsolete version of hadifp as of 10-Aug-2026. (Contributed by BJ, 11-Aug-2020.) (Proof modification is discouraged.) (New usage is discouraged.)

Conclusion
\( \vdash \text{ hadd } ( \varphi , \psi , \chi ) \leftrightarrow \operatorname{if} ( \varphi , \psi \leftrightarrow \chi , \psi \veebar \chi ) \)
Proof
l0
had1OLD
had0OLD
casesifp l0 _