Usually, we use double arrows for implications: A⇒B. You can use a crossed out double arrow for does not imply: A⇏B.

What does → mean in logic?

The → symbol is a connective. It's a symbol which connects two propositions in the context of propositional logic (and its extensions, first-order logic, and so on). The truth table of → is defined to be that p→q is false if and only if p is true and q is false.

What is a symbol for not?

The standard logical NOT symbol is ¬, which corresponds to EBCDIC code point X'5F'.