A set that is not convex is called a non-convex set. A polygon that is not a convex polygon is sometimes called a concave polygon, and some sources more generally use the term concave set to mean a non-convex set, but most authorities prohibit this usage.
In either case you don't need to deal with the absolute value. A rectified sine wave is a periodic signal with a period equal to half of the full sinusoid, I would write the sine in exponential form and integrate over one period to find the series coefficients.
Main menu. Rectified tile is tile that has been mechanically finished on all sides to achieve uniformity and precision. During the manufacturing process, an extra step is taken to grind the tile to precise and consistent dimensions. The most sought after feature of rectified tile is that the uniform size allows for tile to be installed with narrow grout joints. The narrow grout joints create a seamless, continuous look that is desired by designers. It is recommended by the industry that grout joints for rectified tile must be at least 1/8â wide.