I am sorry. By small I meant more like 20 cities. You can formulate a simple optimization problem and solve it with lot of commercially available solvers if you have few cities. The point i was trying to make is that TSPs are not infeasible. They can be solved to optimality given enough time.
If I am not wrong, Concorde TSP solver which is a specialized solver, solves TSPs which have large number of cities.
An efficient solution to TSP would require an efficient solution to all instances of the problem, not an efficient solution for some instances. Most problems are easy in the small cases. And if you are solving special cases, you are solving a decidedly different problem.
>They can be solved to optimality given enough time.
I'm not sure what you mean by this. TSP is infeasible in the sense that it cannot be solved in an efficient amount of time. Naturally, it is solvable if you're given "enough time". It's not an impossible problem.
I should have worded my response better. What I meant was TSPs are intractable. But the author used the word infeasible. In optimization, infeasible and intractable convey different meanings.
If I am not wrong, Concorde TSP solver which is a specialized solver, solves TSPs which have large number of cities.