B Before A
Worse, for general relativity (A) you needed tensors (B) for which you needed calculus (B’) for which you need algebra (B”). That was not an accident; our whole educational system is based on B before A. Here’s a typical scenario: start of September, a new PhD student comes to see me, eager to start research. For that matter the whole educational system is a giant B that you have to do before A – before becoming an active and productive member of society.
Source: billwadge.wordpress.com