NMTS-Group9

Topic

Predicate logic - logical connectives

The purpose of Predicate logic is to avoid ambiguity in sentences by forming formulae out of natural language. Logical connectives are used to create formulae out of sentences with "and", "or", "if/then" and "not". The aim is to state if the given sentence is true or false in a given model.

Examples

and

Symbol: Ʌ
Sentence: Harry is a student and Snape is a teacher.
Formulae: student (harry) Ʌ teacher (snape) = true/false

or

Symbol: V
Sentence: Harry is a student or Snape is a teacher.
Formulae: student (harry) V teacher (snape) = true/false

if/then

Symbol: -->
Sentence: If Harry is a student then Snape is a teacher.
Formulae: [[student (harry) --> teacher (snape)]] = true/false

not

Symbol: ¬
Sentence: Harry is not a student.
Formulae: ¬student (harry) = true/false

Difficulties

• Abstraction of content/natural language
• Understanding the whole process from creating a model to interpret formulae
• Understanding the truth conditions of a formulae with connectives