First Order Logic Flashcards
Is First-Order Logic (Predicate Logic) a meaning representation?
Yes
What does a constant symbol denote?
Exactly one entity, for example:
Scotland, EU, Nagarjuna
Several constants can denote the same entity,
Evening star = Morning star = Venus
“Tyskland” = “Duetschland” = Scotland
What do predicates that have multiple arguments represent?
Relations between the arguments
What does Introduced/3, member_of/2
mean?
The predicate introduced takes 3 arguments (has arity 3) to make it true,
The predicate member_of takes 2 (has arity 2) arguments to make it true.
What are functions?
They map a constant to another entity and they just look like unary predicates, e.g. father(John) = Joe,
captial(Scotland) = Edinburgh
What is an expression that consists only of a predicate that takes a variable and constant as arguments?
A set.
likes(x, Kim) for example would be the set of all people that like Kim
When does predicate that takes a variable and constant as arguments take a truth value?
If the variable is bound by a quantifier
What is quantifier scope ambiguity and can you give an example?
When a sentence has a quantifier that gives it multiple senses because the scope at which the quantifier in the sentence is applied makes the sentence ambiguous. The Part-of-Speech of the sentence is the same for all the senses of a sentence.
“Everybody loves some movie”
“Some movie” could be the same movie that everyone loves or
there exists at least one move that each person loves - they’re not necessarily the same
What problem does reification of events solve?
It solves extending a predicate with more argument and keeping the truth value of the predicate the same. I.e. it solves entailment relatiosnships.
For example the truth value of “John gave Jane the book” should be the same as “John gave Jane the book on Tuesday”
What is reification?
Giveing events the same status as objects, so we can use logical connectives with them.
