Given a relation "R" and "a R b"; if "b R a" is true for all a and b, then the relation R is said to by symmetric.
STATEMENT: Given the relation of "equality" (=), and a = b; if b = a is true for all a and b, then equality is said to be symmetric.
Examples
The statement is TRUE for all a and b (no counterexample can be found).
This is called the symmetric property of equality.
STATEMENT: Given the relation "is less than" (<), and a < b; if b < a is true for all a and b, then "is less than" is said to be symmetric.
Example: Given 1 < 2, it is NOT true that 2 < 1.
Since a counterexample can be found, the statement is NOT true for all a and b.
As a result, the relation "is less than" is NOT symmetric.