Math Logic: Equivalency, Validity, and Consequence

[hossam killua]

i take introduction math logic course in college and professor

ask for relation between equivalent and valdity and consequence

can u help??

 

[Evgeny.Makarov]

It's difficult to say what you mean without knowing more context. Could you provide the definitions of equivalence, validity and consequence that are used in your course?

One possible answer to your question is that two formulas $A$ and $B$ are logically equivalent iff the formula $A\leftrightarrow B$ is valid.