Examples 14.1.1--14.1.5 in the first section each describe an action of a group G on a set X, which will give rise to the equivalence relation defined by G-equivalence. For each example, compute the equivalence classes of the equivalence relation, the G-equivalence classes.
Hint. Example 14.1.1: 0, R2∖{0}. Example 14.1.2: X={1,2,3,4}.