Variable object mapping issue in Python Callbacks with Presolve enabled

Thank you for the clarification.

I understand that using the originally declared variable objects to query values is the most intuitive approach for solving separation problems. However, I am still confused about how the original variables map to the presolved columns, especially when some variables are eliminated during the presolve phase.

For example, let's say I am solving a TSP by generating subtour elimination constraints. To detect a subtour, I need to traverse the graph by checking the values of adjacent arc variables starting from a specific node.

If some arc variables are removed (presolved out), how can I access their values to check the connectivity? Does the interface allow me to query these "missing" variables (e.g., returning a fixed value), or is there a specific method to handle this mapping?