The inference rules

The inference rules are the basic rules of logical calculs of deductive reasoning. It is elementary logical operations.

A rule of inference is a scheme for constructing valid inferences.

These schemes provide syntactic relations between a set of formulas called premises and an assertion called a conlusion.

These syntactic relations are used in the inference process, which leads to new true assertions from others already known.

As mentioned, the application of an inference rule is a purely syntactic. However, it should also be valid. For the requirement of preserving the validity makes sense, we need some form semantics for assertions and inference rules of inference rules themselves.

There are a diferents inference ruls, specifically there are six inferences ruls: modus ponens, modus tollens, syllogism, dilemma, reductio ad absurdum and syllogism disjoint.

The inference rules are not explained why I think it is not necessary.