Let n be a fixed positive integer. Define a relation R in Z as follows: , aRb if and only if a - b is divisible by n. Show that R is an equivalence relation.
Here, we have to a relation R in Z as follows: , aRb if and only if a - b is divisible by n.
Here, aRa is divisible by n and this is true for all integers.
Therefore, R is reflective.
For aRb, is also divisible by n.
or, - (b - a) is divisible by n.
or, (b - a) is divisible by n
Hence, we can write it as bRa.
Therefore, R is symmetric.
For aRb , (a - b) is divisible by n.
For bRc, (b - c) is divisible by n.
Hence, (a - b) + (b-c) is divisible by n.
Or, (a-c) is divisible by n. This can be expressed as aRc.
Therefore, R is transitive.
So, R is an equivalence relation.