"each extra -required- maths course" -- as in required by the school. This is also made clear in the linked paper: http://www.columbia.edu/~jg2394/papers/jobma

"each extra -required- maths course" -- as in required by the school. This is also made clear in the linked paper: http://www.columbia.edu/~jg2394/papers/jobmarket.pdf http://www.columbia.edu/~jg2394/papers/jobmarket.pdf