The functional relation between the impact factor and the uncitedness factor revisited

We give a heuristic proof of the relation between the impact factor (IF) and the uncitedness factor (U), the fraction of the papers that are uncited: U = 1 1 + I F eneralizes the proof of Hsu and Huang [Physica A 391, 2129–2134, 2012] who obtain the same result but based on the assumption of the validity of the Matthew-effect. This new informetric function opens the discussion on universal informetric laws, distribution dependent laws and parameter dependent laws of which examples from the informetrics literature are given.