View source for Equivalent formulas

{{Stub page|grade=B|msg=I'm not exactly sure how to lay this out, but this is based on page 32 in{{rMLFFISWL}}}}
==Statement/Definition==
There's something in the second to last paragraph of page 32 in{{rMLFFISWL}}
==Examples==
Recall {{M|\models A}} denotes that a {{link|formula|FOL}} is [[valid formula|valid]].
# {{M|\models(A\wedge B)\leftrightarrow\neg(\neg A\vee \neg B)}}
# {{M|\models(A\rightarrow B)\leftrightarrow\neg A\vee B}} (see [[negation of implies]])
# {{M|\models(A\leftrightarrow B)\leftrightarrow\neg(\neg(\neg A\vee B)\vee\neg(\neg B\vee A))}}, not even sure I've written this down correctly, never used it
# {{M|\models(\forall x A)\leftrightarrow\neg(\exists x\neg A)}} (would be good one to prove!)
==Proofs==
{{Requires proof|grade=B|msg=See page 32 in<ref name="MLFFISWL"/>}}
==References==
<references/>
{{Formal logic navbox|plain}}
{{Definition|Formal Logic}}{{Theorem Of|Formal Logic}}