ABSTRACT
It is known that the minimum number of distinct eigenvalues c(T) of a symmetric matrix whose graph is a given tree T is at least the diameter d(T) of that tree. However, the disparity c(T) − d(T) can be positive. Using branch duplication and rooted seeds, the notion of the ‘most complex seed’ is introduced, and an explicit upper bound on the disparity is given for any tree of a given diameter.
Disclosure statement
No potential conflict of interest was reported by the author(s).