(geometry) a theorem stating that if a set of points P_i lying on a line is isometrically mapped to points P_i' on a different line, then the midpoints of the segments P_iP_i' also lie on a line.

A surname from Old Norse. / An unincorporated community in Perry County, Kentucky, United States.

plural of puff-box

(biochemistry) The lysis of proteins by means of pepsin