[Help-glpk] subtour elimination

[Livio Bertacco]

Is it possible to "generate" subtour elimination constraints in MathProg
with a single expression (iterated over all subsets of V)?
That is, given a complete graph, I want to add all constraints like:

for all S subset of V:
   Sum, over all (i,j) in S, of x(i,j) <= |S| - 1   

I can't find a way to define the set of subsets of V.

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