Bhatia–Davis inequality

Bhatia–Davis inequality is a mathematical tool that is used to compare the size of two sets. It is like a measuring tape but for comparing sets. It's like if you have two bags of candy and you want to know which is bigger, you can use this inequality to figure it out. To use it you have to count the number of pieces in each bag and compare them using the Bhatia–Davis equation. It will tell you which set has more pieces and is bigger.