Name: _______________________________

1. What is the meaning of the following: "Gamma |= S", where Gamma is a set of propositional formulas, and S a propositional formula.


It means "Gamma entails S", i.e., when all the formulas in Gamma are true, also S is true. (Lecture).
 
 

2. What is the difference between propositional logic and predicate logic?


Predicate logic is propositional logic plus predicates and quantifiers, (Lecture).
 
 

3. What does the sentence "there exits x forall y ( x <= y)" mean, if the domain of the bound variables are the natural numbers and "<=" stands for "is less or equal than"? Is the sentence true or false?


It means that there is a number x, such that all numbers (including itself) is less or equal than it. This is true, since 0 is such a number. (Lecture).
 
 

4. Name one non-classical logic.


Intuitionistic, constructive, modal, fuzzy, linear... (Lecture).
 
 

5. What does a recursive definition consist of?


1. Base clause(s).
2. Recursive clause(s).
3. Final clause. (Lecture).