[Help-glpk] MathProg and Ampl

[Julien THENIE]

Hello all,
I'm trying to translate an Ampl model file in Mathprog, and don't know
how to write the definition of the set "setC" that is an union of
indexed sets.
The ampl formulation is below:
##
set setA;
set setB{setA};
set setC := union {a in setA} setB[a];
##
glpk returns "invalid use of reserved keyword union"...
Thanks for help.

Julien Thénié.
University of Geneva