Here they are defined and explained the nine basic rules which are used in natural deduction. Their objective is to tell us when and how can we add new formulas which continue being true.

Some examples (explained) are in the next section.

- 4.1 Iteration
- 4.2 Conjunction introduction
- 4.3 Conjunction elimination
- 4.4 Implication introduction
- 4.5 Implication elimination
- 4.6 Disjunction introduction
- 4.7 Disjunction elimination
- 4.8 Negation introduction
- 4.9 Negation elimination
- 4.10 No more rules

Daniel Clemente Laboreo 2005-05-17