The paper will show tha bottleneck input service sold by its owner to competitors in the supply of final product must be priced in accord with ECPR if ineffeciency in resource allocation is to be prevented.

Reconsiders Umberto Ricci’s harsh comments on the book of the young Attilio da Empoli about the Theory of Economic Equilibrium and also re-examines da Empoli’s original theses about “ultramarginality” that aroused Umberto Ricci’s fierce criticism. In his reply, da Empoli punctually...