Quantifier

These include:

• $\forall$. For All
• $\exists$. There Exists
• $\nexists$. Does not exist.

Order Of Quantifiers

• If you have two identical quantifiers, the order of them does not matter
• If you have two different quantifiers, the order then matters

Quantifier Exchange

$\neg (\forall x,P(x))\equiv \exists x,\neg P(x)$ $\neg (\exists x,P(x))\equiv \forall x,\neg P(x)$