Set Theory
9.0 Universal set
9.0 Universal set
A set which contains all sets under consideration i.e. a set which is a superset of all the subsets is called an Universal set and is denoted by $U$.
Illustration 19. What universal sets would you propose for each of the following sets.
a. The set of right triangles
b. Set of squares
c. The set of vowels
d. Set of all natural numbers
e. The set of isosceles triangles
Solution:
| SET | PROPOSED UNIVERSAL SET |
| a. The set of right triangles | Set of all triangles |
| b. Set of squares | Set of all four sided polygons |
| c. The set of vowels | Set of all letters of English alphabet |
| d. Set of all natural numbers | Set of all real numbers |
| e. The set of isosceles triangles | Set of all triangles |
