Doubt in the defined comparator

[abhinavgoyal912 (Abhinav Goyal)]

in the video sir defines the comparator to be return true when
“a<=b”. But this will be true for all values less than key… i mean if b is the key then upto 100 the comparator will return true for all values

[amankumarkeshu (Aman Kumar)]

The lower bound function checks the largest element which satisfy that condition.