I am looking for examples of combinatorial optimization problems, if any, which after some theoretical result allowed other representations, thus supporting other formulations (for instance, from discrete to continuous optimization) that led to a closed-form solution.
Thank you in advance for your help.
Even though not exactly the same, I was thinking about something like this: "A good example is in finding the coefficients in a linear regression equation that can be calculated analytically (e.g. using linear algebra), but can be solved numerically when we cannot fit all the data into the memory of a single computer in order to perform the analytical calculation (e.g. via gradient descent)."