Dear AII,

I hope this email finds you well. I am writing to ask for your help with a problem I am facing in my work. Specifically, I am having trouble with the variable in the lower bound of a range set problem.

The specific constraint is as follows:

```
subject to move_forward {i in CARS, k in K_i[i]} :
sum{j in p[i,k] .. p[i,k]+m[i,k]-1} x[i,k,j] = m[i,k];
```

where p[i,k] and m[i,k] are variables, and x[i,k,j] is a 0-1 variable.

When I run this program, ampl will prompt me variable in lower bound of range set, how can I solve this problem. I would greatly appreciate any guidance or advice you could offer on this matter. Please let me know if you have any questions or if there is any additional information I can provide.

Thank you very much for your time and assistance.

Best regards,

liufan

I hope this helps! Let me know if you have any other questions.