## LESSON 2 - WELL DEFINED SETS

The definition of a set must be clear and precise and not lead to ambiguity. It is therefore said that a set must be well – defined. In other words, we must be able to tell if an element belongs to a set. For example, S={short people} is not a well – defined set since short can lead to different interpretations. However, S={persons under 160 cm in height} is a well – defined set because the members of the set can be easily measured and determined.