Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
I suggest a concept of convergence stronger than [sigma]-convergence. This concept, [rho]-convergence, is equivalent to [beta]-divergence in reverse time and implies bounds for convergence speed of merely [sigma]-convergent economies. Empirically, the [rho]-concept detects divergence earlier than the [sigma]- or [beta]-concept.