For example, if we take a 2D point (x, y) and rotate it, you might name the result (x′, y′). Or, the transpose of matrix M might be named M′. In code, we typically just assign the variable a more ...

There are some function names that are ubiquitous in mathematics. For a programmer, these might be analogous to functions. One such example is the sgn function. This is the signum or sign function.