Fallacies in symbolic form

On this occasion I wanted to just give a few examples of argumentative fallacies and how they would look on symbolic form. Since symbols can cut through any haze, these can be used whenever possible to get clarity on what tricky arguments one is facing. Definitely not everything is here, but only some that have caught my eye. (Hope my symbols display well on your browser)

The Post Hoc

If something happens first (P) and something next (Q) one could conclude that

P→Q

4	P	From above
5	Q	From above
6	P→Q	?

Correct

4	P	From above
5	Q	From above
6	P˄Q	Conj 4,5

The most we can say is that something happens and that something else happens. 

P→Q might be True, but it cannot be logically derived from what we have here.

Appeal to Ignorance

You cannot prove you are not a communist, therefore you are one.

1	P→~Q	Premise (enthymeme. If you had proof, then you would not be...)
2	~P	P (You cannot prove…)
3	~~Q	From negating the antecedent 1,2
4	Q	Double negation 3 (Therefore you are a…)

Hmm...1 and 2 makes this one doubly wrong.

What about the ex silentio argument which is nonfallacious and looks similar?

1	Q→R	Premise  (If so-and-so was True, there would be evidence)
2	~R	Premise  (We've looked for the evidence and there's none)
3	~Q	MT 1,2 (So-and-so isn't True)[This one is valid]

Poisoning the well

These examples are taken from Madsen Pirie's How to Win Every Argument. Second lines are paraphrases. The first two seem to focus on the one making the proposal while the third on the proposal itself.

Everyone except an idiot knows…

Only an idiot doesn't know…

∀x(~Kx→Ix)

∀x(~Ix→Kx)

∀x(Ix ˅ Kx)

∀x~(~Ix ˄ ~Kx)

 ~∃x (~Ix ˄ ~Kx)

Only those who are inadequate now advocate…

Everyone except the inadequate do not advocate…

∀x(Ax→Ix)

∀x(~Ix→~Ax)

∀x(Ix ˅ ~Ax)

∀x~(~Ix ˄ Ax)

~∃x (~Ix ˄ Ax)

Choice in education is only a device…

The only thing that is choice in education is a device…

∀x(Cx→Dx)

∀x(~Dx→~Cx)

∀x(~Cx ˅ Dx)

∀x~(Cx ˄ ~Dx)

~∃x (Cx ˄ ~Dx)