ken@ihuxq.UUCP (ken perlow) (01/06/84)
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Does anyone know any definitive rules for computing Roman
numeral values for numbers? There was a style which did not
use any subtraction feature. (14 = XIIII, 1900 = MDCCCC, etc.)
This is not interesting. Furthermore, the subtraction feature
(14 = XIV, 9 = IX, 40 = XL, etc.) seems to be in common use
today, if not back then, especially in writing dates, so that
1900 = MCM. How general is this feature? Is 1999 = MIM?
1995 = MVM? Does 1994 = MXMIV or MCMXCIV or MCMLXLIV or what?
This also brings up the ancillary question: Is there a definitive,
exhaustive character set? There is certainly a wealth of
iconographic evidence for the set R = {I,V,X,L,C,D,M}.
M-with-a-bar-over-it (= 1 Million) seems to be widely used today,
though I suspect it is of more recent origin. Are there others?
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..ihnp4!ihuxq!ken *** ***rjnoe@ihlts.UUCP (Roger Noe @ 41:48:31 N, 88:07:13 W) (01/06/84)
CHOMP THIS >Does anyone know any definitive rules for computing Roman >numeral values for numbers? . . . How general is this [the subtraction] >feature? . . . Is there a definitive, exhaustive character set? Roman numerals are typically used to demonstrate the decimal nature of a number. Thus the only way the "subtraction feature" is generally used is when a 4 or 9 occurs in the decimal (Arabic notation) of a number. In these events, a Roman numeral with a value which is a power of ten (e.g. I=10^0, X=10^1, C=10^2, etc.) is followed immediately by a numeral which has a value five or ten times it. For example, IV=4, IX=9, XL=40, XC=90, CD=400, CM=900, and so forth. The definitive character set is I=1, V=5, X=10, L=50, C=100, D=500, M=1000, and putting a bar over any of these (except I) multiplies its value by 1000. M-bar, or 10^6, is the largest authentic Roman numeral. Apparently the Romans did not have much need to count any higher than a few million. Now there's no reason you can't decide to write IM for 999 rather than CMXCIX, the canonical way to do it. [Yes, in 1999, films and buildings will have MCMXCIX on them, almost certainly not MIM.] It's pretty clear that IM has one interpretation. But what about IVX? Does it have any meaning? Some would say it is the same as IV, because -1-5+10=4. It's usually best to stick with the widely-accepted, commonly-used and well-understood definition which only allows the combinations mentioned above. I have a C program which does just this which I'll send to anyone interested. I've also a closely related program which takes Roman numerals of a much more general nature (e.g. MIM and IVX) and gives the Arabic notation version. Roger Noe ...ihnp4!ihlts!rjnoe
dvk@mi-cec.UUCP (Dan Klein) (01/07/84)
The "current" rules that I am aware of are: 1 5 10 50 100 500 1000 I V X L C D M (and then the bar-over-letter rules) subtraction may only be by the immediately preceding starting with a "1" numeric character, thus: 1999 == MCMXCIX. -Dan Klein, Mellon Institute, Pittsburgh
graham@parsec.UUCP (01/27/84)
#R:ihuxq:-46500:parsec:38000002:000:962 parsec!graham Jan 26 17:20:00 1984 /***** parsec:net.math / ihlts!rjnoe / 6:22 pm Jan 6, 1984 */ CHOMP THIS >Does anyone know any definitive rules for computing Roman >numeral values for numbers? . . . How general is this [the subtraction] >feature? . . . Is there a definitive, exhaustive character set? Roman numerals are typically used to demonstrate the decimal nature of a number. Thus the only way the "subtraction feature" is generally used is when a 4 or 9 occurs in the decimal (Arabic notation) of a number. ...... I have a C program which does just this which I'll send to anyone interested. I've also a closely related program which takes Roman numerals of a much more general nature (e.g. MIM and IVX) and gives the Arabic notation version. Roger Noe ...ihnp4!ihlts!rjnoe /* ---------- */ I would like a copy of the C program which you mentioned. Marv Graham; ConVex Computer Corp. {allegra,ihnp4,uiucdcs,ctvax}!parsec!graham O: (214)669-3700 H: (214)931-7924
crandell@ut-sally.UUCP (02/01/84)
> I've also a closely > related program which takes Roman numerals of a much more general nature > (e.g. MIM and IVX) and gives the Arabic notation version. I think someone should point out that the traditional syntax of Roman numerals prohibits strings of symbols of ascending order whose length exceeds two, for the rather obvious reason that subtraction is not associative. For example, does IVX mean (IV)X or I(VX)? Standard usage has never required the members of the ascending sequence to have adjacent values; e.g., 9 has generally been IX. (The sequence VIIII has been seen, but usually only in the same context as IIII for 4; VIV is essentially unheard of.) -- Jim Crandell, C. S. Dept., The University of Texas at Austin {ihnp4,seismo,ctvax}!ut-sally!crandell