Category:Propositional logic (Aussagenlogik)

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Overview

This page lists the most important terms and laws for the BFH module: Diskrete Mathematik I (BZG1155pa) 25/26

Propositional logic

Propositional logic (Aussagenlogik) is a formal system in logic that studies propositions and their relationships through logical connectives. It is the foundation of mathematical logic, computer science, and digital circuit design.

Propositions

A proposition (Aussage) is a declarative statement that is either true (wahr) or false (falsch), but not both. Examples:

  • "It is raining."
  • "2 + 2 = 4."
  • "The moon is made of cheese." (false, but still a proposition)

Syntax

Propositional formulas are built recursively:

  1. Every proposition symbol (p, q, r, …) is a formula.
  2. If φ is a formula, then ¬φ is a formula.
  3. If φ and ψ are formulas, then (φ ∧ ψ), (φ ∨ ψ), (φ → ψ), (φ ↔ ψ), … are formulas.

Semantics

The truth value of a formula is determined by the truth values of its components according to truth tables. This is called **truth-functional semantics**.

Terms

These are the basic logical connectives and symbols used in propositional logic.

See also

Logic Laws

These are the fundamental logical laws (Gesetze der Aussagenlogik) that are used to transform and simplify logical expressions.