# Inference Rule

Definition. An inference rule is a primitive valid argument form. Each inference rule enables the elimination or the introduction of a logical connective.

Most inference rules have names that consist of:

- a logical connective,
- a letter:
- βiβ indicates that the rule introduces a formula that contains the connective
- βeβ indicates that the rule eliminates (i.e., uses) a formula that contains the connective

### CS241E

Oh my god, I am also seeing this concept in CS241e.

An inference rule is a collection of zero or more premises and a conclusion. The premises are written above a horizontal line and the conclusion below the line. The rule asserts that if the premises hold, then the conclusions holds.

### Informal Meaning (from PD20)

βAn inference is the process of using information, data and evidence to justify that the conclusion is true. An inference is a conclusion or opinion that is formed because of known facts or evidence.β