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.
Plywood long ago lost its market leadership to oriented strand board (OSB), which is now the most-used sheathing and subflooring material. Estimates put its market share as high as 75%, with much of that dominance thanks to cost-conscious production builders.hen plywood gets wet, it tends to swell consistently across the sheet, and then returns to its to normal dimensions as it dries out. It dries out relatively quickly, and the swelling is usually not enough to affect floor or roof finishes. OSB takes longer to get wet than plywood but also takes longer to dry out.