Ramsey number

The Ramsey number is a concept in mathematics that determines the minimum size of a complete network (or graph) needed so that no matter how you connect points with two different types of lines (like red and blue), you'll always find a smaller group of points entirely connected with one color. For example, it shows the smallest number of people needed so that you are guaranteed to have either a group of friends all mutual or a group of strangers all mutual. Essentially, it measures the inevitability of certain patterns emerging in large, randomly connected systems.