Problem for every graph , we let denote the line graph of . Given that is a tree, can we determine it from the integer sequence ?
Graph reconstruction is a notoriously difficult subject. This conjecture is an unusual type of reconstruction problem where our class of graphs is very limited - just trees, but we are also given relatively little information - just a sequence of integers.
Bibliography
[GR] C. Godsil and G. Royle, Algebraic graph theory. Graduate Texts in Mathematics, 207. Springer-Verlag, New York, 2001 (page 18).
* indicates original appearance(s) of problem.