Let a Patch be given by the map
, where is an open subset of , or more
generally by
, where is any Subset of . Then (or more
generally, ) is called the trace of **x**.

**References**

Gray, A. *Modern Differential Geometry of Curves and Surfaces.*
Boca Raton, FL: CRC Press, pp. 183-184, 1993.

© 1996-9

1999-05-26