Normally when given a question like $Q \wedge P, R \vdash P \wedge R$
I can do box proof like:
$\dfrac{\dfrac{Q \wedge P^{~\text{(assumption)}}}{P}{^\text{($\wedge$-elimination)}}\quad R^{~\text{(assumption)}}}{P\wedge R}{^\text{($\wedge$ introduction)}}
\\\text{ (Q.E.D.)}$
But what about when I'm asked to prove $A \rightarrow (B \rightarrow A)$?
Do I just start with assumption as $A$?
Best Answer
Yes, assume $A$. Next assume $B$, and lo, somehow derive $A$ from those assumptions. Finally use conditional introduction a few times to discharge those assumptions.