When dealing with particular situations in mathematics, it is often easier to have a set which contains all the elements we deal with. This set is called a universal set and we want to define it properly.
Definition: Universal Set
A universal set $U$ is a set of elements fulfilling all the necessary or sufficient properties that we deal with in a particular situation.
In a Venn diagram, we draw the universal set as a frame in which we place the sets of our consideration (here a set $A$).
- If you are considering all vans, the universal set could be the set of all cars.
- The set of all possibilities to win in a coupon-based lottery could be considered as the universal set of all the possibilities printed on the coupons produced for this lottery.
- The set of all possible words which can be constructed from Latin letters is the universal set of all words which have a meaning in the Englisch language.
| | | | | Contributors: bookofproofs | References: , 
This work is a derivative of:
Bibliography (further reading)
 Kohar, Richard: “Basic Discrete Mathematics, Logic, Set Theory & Probability”, World Scientific, 2016
 Reinhardt F., Soeder H.: “dtv-Atlas zur Mathematik”, Deutsche Taschenbuch Verlag, 1994, 10