Given a chessboard n×n, where n≥4 and p=n+1 is a prime number. A set of n unit squares is called tactical if after putting down queens on these squares, no two queens are attacking each other. Prove that there exists a partition of the chessboard into n−2 tactical sets, not containing squares on the main diagonals.Queens are allowed to move horizontally, vertically and diagonally. number theoryprime numberscombinatoricsChessboard