Hey everyone,(adsbygoogle = window.adsbygoogle || []).push({});

Thanks for the help in advance. I am having trouble deriving a tautology from no premises.

I am trying to derive:

(X <-> Y) v (X <-> -Y) "-" meaning not.

However, I keep getting stuck. It seems very similar to the Law of the Excluded Middle but I am having trouble changing that derivation. Any help or suggestions of where to start would be appreciated.

Thanks

Jax

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# Having trouble with Logic Derivation - please help

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