Material Equivalence
editThere is an error on material equivalence, both conditions are necessary to make p equivalent to q:
- image: (p is equiv. to q) means, either (if p is true then q is true) or (if q is true then p is true)
- correct: (p is equiv. to q) means, (if p is true then q is true) and (if q is true then p is true)
![{\displaystyle (p\equiv q)\equiv [(p\rightarrow q)\lor (q\rightarrow p)]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/b819df8c2793cc96085b75898788e24223c09f42)
![{\displaystyle (p\equiv q)\equiv [(p\rightarrow q)\land (q\rightarrow p)]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/399f61e37afcde148268f5ac47e8d70fb8b549fe)
