1974 (Publication #19)
Triple Points and Surgery for Immersed Surfaces
Proc. A.M.S. 46 (1974), 407-413.
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The number of triple points of a sufficiently general immersion of a smooth or polyhedral closed 2-dimesnional surface into E^3 is congruent modulo 2 to its Euler characteristic. The approach used to prove this result involves elementary notions of modification of surfaces via surgery.