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Enumeration Problem: Triangulations




The number of output vertices might be exponential in the size of input, while it can be very small. The upper bound in the two dimensional case is attained by any convex set of points and can be explicitly written as the (n-1)st Catalan number. It is easy to construct an example for which the number of triangulations is small (polynomial in n and d).

Is there any algorithm for the triangulation enumeration enumeration problem which runs in time polynomial in both the input size and the output size?
Is there such an algorithm whose space complexity is polynomial in the size of input and the size of largest triangulation?
The answer to the question (b) is not known in general. For the 2 dimensional case, the reverse search algorithm [AF96] gives "yes" answer to (c).
A closely related problem of enumerating all regular triangulations has been studied recently. This problem appears to behave much nicely and some efficient algorithms have been proposed. In fact, the corresponding question (c) has been affirmatively answered by Masada.

Komei Fukuda
Wed Jun 12 17:26:21 GMT+0100 1996