On page 12 of the book I'm stumped.
It says that the 'column numbers in which the leading entries 1 occurs' are denoted by , where r is the number of nonzero rows.
They give an example, where r=3, which means there are 3 non-zero rows in the matrix (as far as I can tell). Then the give some values for the c's. I undersatnd how the obtained the first 3 values:
, , .
However, I don't see how they obtained values for and .