Question

State which of the following sets are empty and which are not?
i. The set of lines passing through a point.
ii. Set of odd natural numbers divisible by 2.
iii. {x: x is a natural number, x<5 and x>7}
iv. {x: x is a natural number, x<5 and x>7}
v. Set of even prime numbers

Answer 1

i. Not empty
ii. Empty
iii. Empty
iv. Empty
v. Not empty

Answer 2

i.Non-empty(infinite)
ii.Empty(Finite)
iii.Empty(Finite)
iv.Empty(Finite)
v.Non-Empty(Finite) with cardinal no 1.
ii to iv have cardinal no 0.