var x >= 0;

param delta_min default 1e-4;
param delta_max default 2e-4;

r1: x >= delta_min;
r2: x <= delta_max;

# should result in x == delta_min or infeasible
minimize f: x;
solve;

# for delta_min next to 1e-4, x == 0
display x;
printf "x = %.16f\n", x; 

display delta_min;
display delta_max;

end;