👉 In mathematics and computer science, "coextension" is a concept that refers to an extension of a function or relation from one domain into another. This extension can be understood as a modification or addition of the original domain's structure or behavior. For example, consider two functions f(x) and g(x), where x is a variable in the first domain, and y is a variable in the second domain. If we want to extend f(x) by adding an additional argument to it (so that
