A sparse ruler is called optimal if it is both minimal and maximal. Since the number of distinct pairs of marks is m ( m â 1 ) / 2 {\displaystyle m(m-1)/2} , this is an upper bound on the length L {\displaystyle L} of any maximal sparse ruler with m {\displaystyle m} marks.
1 One 23/32-inch 4x8-foot plywood piece weighs approximately 67 pounds, while a piece of OSB of the same dimensions weighs approximately 78 pounds.
edit Cost of Plywood vs OSB. OSB is cheaper than plywood by about $3 to $5 per panel. For a typical 2,400 sq. ft. home, OSB is about $700 less expensive compared with plywood if used as the subfloor, sheathing, and roof decking.