Monotonicity criterion

Monotonicity criterion is like playing with toys where you have to follow a set of rules. Let's say you have a toy car and you want to make it go faster. But there are rules that say you can only push it forward and not backwards. That's a monotonicity criterion.

In simpler terms, monotonicity criterion is a rule that says when something increases or decreases, it can't reverse its direction. Imagine you are climbing a staircase. You can't climb up a few steps and then suddenly go back down. You have to keep moving up until you reach the top.

This criterion can be used in different areas like math, economics, and engineering. For example, if you are studying how the temperature changes in a room, you can use monotonicity criterion to predict that if the temperature rises, it won't suddenly drop down and keep rising until it reaches a certain point.

So, the monotonicity criterion is like taking one step at a time and not going back. It helps us make predictions and understand how things change.