* Shitkovski AMPL model  (translation to GAMS)

Set I /1,2/;

Variable  x[I],Obj;

Equation Eq_1,Eq_2,Def_obj;

Def_obj..     Obj =e= 100*sqr(x['2'] - sqr(x['1'])) + sqr(1 - x['1']);

Eq_1..              -x['1'] + sqr(x['2']) =g= 0;
Eq_2..               sqr(x['1']) - x['2'] =g= 0;

x.lo['1'] =  -1/2;
x.up['1'] =   1/2;
x.up['2'] =   1  ;


x.l['1'] =  -1/2;
x.l['2'] =   1  ;

*x.l['1'] =  0;
*x.l['2'] =  0;

Model hs017 /all/;
Solve hs017 using nlp minimaze obj;

display x.l  ;
display obj.l;

*optimal obj =  1  ;