Let

>let

I shouldn't have laughed as hard as I did at this.

Let [math]OP \in\ \{x| x \space is \space a \space faggot\} [/math]

>(Why?)

>necessary and sufficient

That cat has eosinophilic granuloma on its lower lip. It is suffering from allergic reaction.

I don't get it

>prove that

>which we state without proof

>left as a exercise for the reader