Propositional calculus
Propositional calculus is the simplest and most basic branch of logic because the propositions are unanalysed.
The symbols used in propositional calculus are:
- variables
- operators
- brackets
Variables
Variables, such as p, q and r represent unspecified propositions in formulas into which only sentences may be inserted.
Operators
Operators create a new proposition from one or more given propositions which are called the arguments of the operator.
The operators are:
Brackets
Brackets make it possible to distinguish, for example, between
In other words, the first proposition is “both p and either q or r”, and this differs in meaning to the second proposition “either both p and q or r”.