 Solution

ID: past-exam-of-the-mathematical-methods-i-course-of-the-university-of-oxford/2014/12/i/solution

n

freely chosen diagonal entries and

n (n - 1) /2

freely chosen entries above the diagonal. The entries below are then fixed by symmetry. Consequently

dim S = \frac{n ( n + 1 )}{2} .

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