Introduction to Proposition

• A proposition is a declarative sentence that is either true or false, but cannot be both.
• What are the Five Logical Connectives?

  1. Conjunction
  2. Disjunctions
  3. Implication or Conditional
  4. Biconditional
  5. Negation
• The symbol used to represent conjunction is "and" (∧).
• The symbol used to represent disjunction is "or" (∨).
• The symbol used to represent implication is "implies" (→) or "if...then..." (↔)
• The symbol used to represent negation is "not" (¬)
• The symbol used to represent biconditional is "...if and only if..." (⇔)
• Logical connectives can also be represented using symbols called truth tables.
• Talisay is a city in Cebu


  Proposition
• 2+3=6


  Proposition
• She is a Filipina.

  Proposition
• Ouch!


  Not Proposition (an exclamatory sentence)
• 3x+2=5


  Not Proposition (x doesn't have a value)
• This sentence is true

  Not Proposition (a paradox)