Predicate Logic

Question 1

What is a constant?

Answer 1

the names of individual things e.g James

Question 2

What do we use for constants?

Answer 2

lower case letters except ‘x’, ‘y’ and ‘z’
e.g. James is ‘j’

Question 3

What is a predicate?

Answer 3

What you’re left with when you remove a name from a sentence e.g. ‘James is a man’ becomes ‘…is a man’

Question 4

What do we use for predicates?

Answer 4

capital letters e.g. M=is a man

Question 5

Translate ‘James is a man’ into predicate logic

Answer 5

Mj
Key:
M= is a man
j= James

Question 6

Translate ‘Marie was tall but Janice was short’ into predicate logic

Answer 6

Tm & ~Tj

otherwise translates to: Marie is tall and Janice is not tall

here, but is used as a synonym for and

Key:
T= is tall
m= Marie
j= Janice

Question 7

What’s an example of a relational predicate?

Answer 7

‘is taller than’
‘is louder than’
‘is kinder than’ etc

Question 8

How would you write, Marie is taller than Janice using a relational predicate?

Answer 8

Tmj

T= is taller than
m= Marie
j= Janice

Question 9

How would you write, Marie is between Janice and Amelia using a relational predicate?

Answer 9

Bmja

B= is between
m= Marie
j= Janice
a= Amelia