Hello i have a problem with the display of a nonlinear objective function in the equation listing.
I wonder if we can print the actual nonlinear or quadratic function ?

Note from documentation
Nonlinear equations are treated differently. If the coefficient of a variable in the equation listing is enclosed in parentheses, then the corresponding constraint is nonlinear, and the value of the coefficient depends on the activity levels of one or more of the variables. The listing is not algebraic, but shows the partial derivative of each variable evaluated at their current level value

The GAMS Equation listing does not help. If you want to see the unrolled scalar model, you can “solve” with the Convert solver (https://www.gams.com/latest/docs/S_CONVERT.html). Convert creates a file gams.gms with the individual variables and equations. The naming of your original variables and equations is lost. We have now x1,x2,… and e1,e2,… Using the second default output the dict.txt file (a mapping between the new names and the GAMS names) plus a little sed script you can reintroduce the GAMS names in the scalar model. Find details at https://www.gams.com/latest/docs/S_CONVERT.html#CONVERT_THE_GAMS_SCALAR_FORMAT.