Venn Diagram –
Venn diagrams are set diagrams drawn to represent sets. A closed curve or a rectangle is drawn and the points of the interior of the closed curve represents the elements of the set under consideration. The diagrams can be identified –
(i) By using the letter name of the set illustrated, or
(ii) By writing the members of the set within a curve as shown in figure
It may be noted that only the points in the interior of the closed curve belong to the set. A point on the boundary of the region does not belongs to the set.
The universal set is generally represented by the set of points of a rectangular region as shown in the figure..
After having got the universal set represented by the interior region of the rectangle, smaller closed geometrical figures are used to represent various subsets of the universal set.
Below figure illustrates two intersecting sets, A & B as subsets of universal sets ξ.
Below figure shows two non intersecting sets, A and B as subsets of a universal set ξ.
Below figure shows set B as a proper subset of set A
Below figure shows the universal set is represented by a rectangle and the set A which is contained in the universal set by a circle ‘a’ is an element of set A, a ∈ A.
Your second block of text...