Before revision:  The Gini (g) index, giving the overall inequality is the most common , while the recently introduced Kolkata (k) index gives a measure of 1-k fraction of population who possess top k fraction of wealth in the society.
After revision:  The Gini (g) index, giving the overall inequality is the most commonly used , while the recently introduced Kolkata (k) index gives a measure of 1-k fraction of population who possess top k fraction of wealth in the society.