Normal sudoku rules apply. Digits in cages do not include repeat digits, and sum to the indicated total. Digits along indicated diagonals must add to the indicated total. Repeats are permitted along such diagonals. Each row, column, and 3x3 box contains exactly one 'negator' cell. Digits in these cells must be subtracted, rather than added, to achieve the given cage or diagonal totals. The nine 'negator' cells are also a set of the digits 1-9.