It turns out that Saudi Arabia is not the only country with an aversion to symbols reminiscent of the cross. It turns out that in some circles in Israel, the plus-sign is avoided due to its resemblance to the cross and is replaced with a version that looks like this: ﬩ It is actually in Unicode, at codepoint U+FB29, dubbed HEBREW LETTER ALTERNATIVE PLUS SIGN.
On the basis of information from a few correspondents, it seems that the truncated plus sign turns up in some ulpan (Hebrew language classes for non-Israelis) and in the lower grades of primary school. It seems to be unheard of at the university level. A friend reports that her daughter was taught arithmetic with both the truncated plus sign and with a division sign ÷ with the horizontal removed, so that it looks like this: ∶ . Now in grade 5 her class is using the usual plus-sign but is still using the modified division symbol. I'm guessing that the distribution of usage has to do with variation in the influence of the religious right.
I suppose that this is marginally saner than the Saudi objection to X since a plus sign more closely resembles a cross, but however you cut it, it is still pretty stupid. I'm a Jewish atheist who has read and written many a plus-sign and not once have I felt oppressed by the Christian overtones of mathematical notation.
Addendum: Several people have written to tell me that the colon-like division sign is used in elementary education in their country. This seems to be the case in France, Germany, the Netherlands and Norway at least. So there seem to be two different things going on in Israel - cross-avoidance with the truncated plus-sign, but ideology-free regional variation with the division-sign.Posted by Bill Poser at January 18, 2007 03:57 PM