Introduction to Applications of Propositional Logic

Two applications of propositional logic are mentioned here:

• Translating English Sentences
• Boolean Search

Translating of English Sentences

• Propositional Logic helps to remove any ambiguity in English sentences
• English sentences are translated into compound propositions using propositional variables and logical connectives
• These compound propositions are analyzed to determine their truth value

Example 1:

• "You can access the Internet from campus only if you are a computer science major or you are not a freshman."
• a = "You can access the Internet from campus,"
• c = "You are a computer science major,"
• f = "You are a freshman,"
• The above English sentence can be translated in propositional logic as
• a → (c ∨ ¬f)

Boolean Searches

• Most search engines (e.g. google) uses propositional logic to find web pages on some subject
• These searches are called Boolean Searches as logical connectives (AND, OR, NOT) are used to match keywords in web pages

Example 2:

• You type keywords - British Universities - in google search bar to search for universities in Britain.
• Google uses Britain AND Universities to look for pages containing the both keywords Britain and Universities.