----- Original Message ----- From: "Yaakov Stein" <yaakov_s@xxxxxxx> To: "Tom.Petch" <sisyphus@xxxxxxxxxxxxxx>; "Elwyn Davies" <elwynd@xxxxxxxxxxxxxx> Cc: "ietf" <ietf@xxxxxxxx> Sent: Sunday, February 19, 2006 7:10 AM Subject: RE: 'monotonic increasing' Actually, even mathematicians don't agree on the wording here. In analysis we commonly talk about monotonic functions, which can be either monotonically increasing ( x <= y => f(x) <= f(y) ) or monotonically decreasing ( x <= y => f(x) >= f(y) ). Since analysis deals with continuous entities, the distinction of nondecreasing vs. increasing is usually not important, and thus not worried about. However physicists tend to make the distinction by saying "nondecreasing". In dealing with sequences, the distinction is almost universally made between nondecreasing ( x_n <= x_n+1) and increasing (x_n < x_n+1) although the European school prefers stressing the difference by using the word "strictly" instead. To make things more confusing, in order theory (where you would expect the wording to be the tightest) the wording used is monotone (for "increasing") and antitone (for "decreasing"). Of course there the distinction between nondecreasing and increasing is not important since the description is of a (partial) order relation, and if that relation includes equality as a special case than you get one variety, while if not you get the other. Y(J)S Beautiful (as mathematics always is). But just to be clear, if you saw a reference to 'monotonic increasing' in an American journal, say of applied mathematics, would you be sure you understood what was meant? And if so, would that be S_i+1 >= S_i U+2200 i or S_i+1 > S_i U+2200 i? Tom Petch _______________________________________________ Ietf@xxxxxxxx https://www1.ietf.org/mailman/listinfo/ietf