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determinant definition...can't figure out what the index of summation
is
Posted:
Nov 6, 2009 10:02 PM
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Hello,
I am studying a definition of a determinant in a textbook. The left
the index of summation out, which makes it very confusing. I am going
to type the definition they wrote here. I am hoping someone could
tell me what the index should be. Usually there is something like i=1
underneath the big sigma symbol, and then an n above the symbol (which
would tell you to sum the terms one by one up to the number n). But
they did put any index of summation in the definition. Here it is:
"det(A) = ? (+/-) (a1j1)(a2j2)...(anjn) where the summation is over
all permutations j1j2...jn of the set S={1,2,....n}. The sign is
taken as + or - according to whether the permutation j1j2...jn is even
or odd."
Is the index of summation supposed to be j=1 to n? I can't understand
why the left this information off.
Note: the numbers in a1j1 etc. in the definition above are supposed to
be subscripts, but I don't know how to type those into this type of
newsgroup text).
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