Rank polymorphism means that a function can be polymorphic in the additional dimensions of arrays. For example, if you write a function that takes a 2x3 and a 4x5 array, it can also work on 10x15x2x3 and 10x15x4x5 arrays by broadcasting.

If rank polymorphism results in accepting both 4x2x8 and 3x7, then that means the function was a function on elements to begin with. Which is possible, but not the most interesting application of rank polymorphism.

> Rank polymorphism means that a function can be polymorphic in the additional dimensions of arrays. For example, if you write a function that takes a 2x3 and a 4x5 array, it can also work on 10x15x2x3 and 10x15x4x5 arrays by broadcasting.

Thanks, this is what I was ineloquently attempting to describe with "A function that can take as input a 4x2x8 matrix or a 3x7 matrix."