System F

System f is a way of classifying functions and data types. It uses something called "type variables" to group things together. Type variables are like labels - they help us identify which functions and data types belong together. For example, if we have a type variable called "Number", it might tell us that any function that works with numbers, like multiplying them, belongs to the Number type variable. System f helps us make sure that functions and data types are used properly and don't confuse us.