Mathematical relations necessary for the calculation of the
previously introduced15 topological resonance energy, TRE, are
derived. TRE, as defined in ref. 15, was rather inconvenient for
numerical calculations. In the present work these computing difficulties
are overcome.
Acyclic characteristic polynomial pac and acyclic spectrum of
a graph are defined and their close relationship to TRE is demonstrated.
Hence, the evaluation of pac is the crucial .step in the computation
of TRE\u27s. A graphical procedure is described and exemplified
for the determination of P"c\u27s both for simple graphs and
for graphs with loops and weighted edges