“…Moreover, for a given set of {q, n, l}, the QNMs with a different number m are degenerate (i.e. have the same complex frequency ω q,n,m,l ), and the sum can be recast in the form q,n,l with "effective" mode volumes defined as 1/V q,n,l ≡ m 1/V q,n,m,l (see Appendix E in [6] and also [8]).…”