Trace

the trace of a matrix is the sum of prime diagonal elements.

example:

1 2 3 1 2 3 1 2 3

trace(a) = 1 + 2 + 3 = 6

properties of trace

• (A^t)^t = A
• (AB)^t = A^t + B^t
• (A + B)^t = A^t + B^t
• (A^t)^n = (A^n)^t
• Trace(A+B) = Trace(A) + Trace(B)
• Trace(kA_n) = K * Trace(A_n)