Suppose ,instead of the usual x,y coordinate system with an I basis vector along the x -axis and a corresponding j basis vector along the y-axis we instead have a different pair of basis vectors ,call them e and f along their respective axes.
I have seen that this is an important subject in maths
My question is what physical applications does such a model apply to?
I am asking here because I have devoted quite a lot of time in the past to understanding convectors and the dual...