Axioms for Shortest Paths Suppose we have an undirected weighted graph $G = (V, E, w)$ (with non-negative weights). Let us assume that all shortest paths in $G$ are unique. Suppose we have these $\binom{n}{2}$ paths (sequences of unweighted edges), but do not know $G$ itself. Can we produce any $G$ that would have given these paths as the shortest in polynomial time? The weaker version: can we decide in polynomial time if such $G$ exists?

The obvious necessary condition is the following: for every pair of paths their intersection is a path too. Is this condition sufficient?
You can write the problem as an LP, can't you?  For any two vertices u, v, and any path P from u to v, the weight of P is greater than or equal to the weight of the given shortest path between u and v. These are all linear inequalities, and even though there are exponentially many, the separation problem is in P (it's just an all-pairs shortest path problem).  So, you can use the Ellipsoid algorithm to solve it.