Bifurcation diagrams of periodic windows of scalar maps are often found to
be not only topologically equivalent, but in fact to be related by a nearly
linear change of parameter coordinates. This effect has been observed nume
rically for one-parameter families of maps, and we offer an analytical expl
anation for this phenomenon. We further present numerical evidence of the s
ame phenomenon for two-parameter families, and give a mathematical explanat
ion like that for the one-parameter case. (C) 1999 Elsevier Science B.V. Al
l rights reserved.