Proposition (logic)

In logic, a formal or natural language expression that can either be true or false.

Examples:

• “true” → a proposition with the value true.
• “2 + 3 = 5” → proposition with the value true.
• “Paris is the capital of France.” → a proposition which is true.
• “Japan is an island in the Atlantic ocean.” → a proposition which is false.
• “2 + 3” → not a proposition, as it has a value (“5”) that is neither true nor false.
• “The longest river in Europe” → not a proposition, as it has a value (“Danube”) that is neither true nor false.

• Contradiction
• Mu
• Tautology