Mathematical Logic [Lec07 Natural Deduction System]

CS 210: Mathematical Logic Notes

Natural Deduction System (ND)

$\perp$ 代表“矛盾”

Derived Rules

1. 
   $$\begin{align}
   &3.\ p \qquad Assumption \
   &4.\ q \qquad \rightarrow \mathrm{e}:1,3 \
   &5.\ \perp \qquad \lnot \mathrm{i}:3,5
   \end{align}$$
2. PBC (Proof by Contradiction)反证法
3.