[net.math] With Hanging Ribbons

trainor@ucla-cs.UUCP (02/21/86)

Does anyone know of any references to work on lemniscate curves
with an arbitrary number of foci.  Imagine n foci points in the
      _   _        _            _
plane F , F , ..., F .  A point M moves along the curve such that
       1   2        n

the product of its distances from each foci is constant.

   n
-------
 |   |      _  _
 |   | dist(M, F )   =   k
 |   |          i
 i = 1

What about choosing the n foci and constant k such that you come
arbitrarily close to a given non-self-intersecting closed curve.
This was briefly mentioned in this little green book _Remarkable
Curves_ by A.I. Markushevich (translated from Russian), in which
he says, "...proved rigorously in higher mathematics, and the proof
is very complicated."

	Douglas

ARPA: trainor@locus.ucla.edu
UUCP: ...!{sch-loki,silogic,randvax,ihnp4,sdcrdcf,trwspp,ucbvax}!ucla-cs!trainor