09.12.2012 Views

Concrete mathematics : a foundation for computer science

Concrete mathematics : a foundation for computer science

Concrete mathematics : a foundation for computer science

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

Does rocky road<br />

have fudge in it?<br />

2.4 MULTIPLE SUMS 37<br />

the sum of all elements on or above the main diagonal of this array. Because<br />

ojok = okoj, the array is symmetrical about its main diagonal; there<strong>for</strong>e Sy<br />

will be approximately half the sum of all the elements (except <strong>for</strong> a fudge<br />

factor that takes account of the main diagonal).<br />

Such considerations motivate the following manipulations. We have<br />

Sq = x CljClk = t ClkClj = t ajak = Sn,<br />

l

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!