Discrete Mathematics

110 DISCRETE MATHEMATIC..._

________________________

_

It

is often desirable to focus attention

on

some set U

of

elements. All the sets to

be

considered are

subsets

of

this set. In this case, we shall refer to U as the universal set.

2.2

SET

SPECIFICATION

2.2.1

Explicit

We

have already used this method

to

specify a set. Here the elements

of

a set are listed and the list enclosed in

a pair

of

braces ( {}

).

Some examples are:

(i)

WEEKDAYS=

{Monday, Tuesday, Wednesday, Thursday, Friday}

(ii)

COURSES = {Embedded systems, Real-time systems}

(iii)

X=

{5, 6, 2, 3, 7}

(iv) DECIMAL-digits=

{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}

Clearly this specification ...