There appears to be no consistent name for these curves in the literature on the Lambek–Moser theorem. Both Dijkstra (1980) and Garry (1997) draw these curves and note their reflection property but do not distinguish the curves from the functions they graph nor give them a separate name. A histogram is a type of bar chart for a discrete sequence of data values; the curves called histograms here resemble the histograms of the sequence of function values in this sense. Dijkstra, Edsger W. (1980), On a theorem by Lambek and Moser(PDF), Report EWD753, University of Texas Garry, Y. K. K. (1997), "Inverse sequences and complementary sequences"(PDF), Mathematical Excalibur, 3 (4): 2
There appears to be no consistent name for these curves in the literature on the Lambek–Moser theorem. Both Dijkstra (1980) and Garry (1997) draw these curves and note their reflection property but do not distinguish the curves from the functions they graph nor give them a separate name. A histogram is a type of bar chart for a discrete sequence of data values; the curves called histograms here resemble the histograms of the sequence of function values in this sense. Dijkstra, Edsger W. (1980), On a theorem by Lambek and Moser(PDF), Report EWD753, University of Texas Garry, Y. K. K. (1997), "Inverse sequences and complementary sequences"(PDF), Mathematical Excalibur, 3 (4): 2