tih@barsoom.nhh.no (Tom Ivar Helbekkmo) (08/17/90)
I've been trying to find out these past couple of days what the origin of the name of the character/symbol "nabla" is. Nabla is used (as far as I can gather) primarily in mathematics, and is a greek delta turned upside down (i.e. a triangle standing on one of its points). In mathematics, I'm told it's also called the "del operator". The name nabla seems to be common in typesetting systems (TeX has it), and this is what the character was called when it was part of ASCII. (The position it held in the ASCII table is now occupied by '@'.) So far, I've found that it's not a Greek or Hebrew letter (as I first thought it must be), and neither is it (I believe) of Phoenician or Egyptian origin. If anyone can tell me why nabla is called nabla, I'll sleep better at night! :-) Oh, and if you're reading this in sci.math, please respond by email, as I don't follow that group... -tih -- Tom Ivar Helbekkmo, NHH, Bergen, Norway. Telephone: +47-5-959205 tih@barsoom.nhh.no -- edb_tom@debet.nhh.no -- tih@macpost.nhh.no
lowj_ltd@uhura.cc.rochester.edu (John "Travis" Low) (08/18/90)
tih@barsoom.nhh.no (Tom Ivar Helbekkmo) writes: >I've been trying to find out these past couple of days what the origin >of the name of the character/symbol "nabla" is. Nabla is used (as far >as I can gather) primarily in mathematics, and is a greek delta turned >upside down (i.e. a triangle standing on one of its points). In >mathematics, I'm told it's also called the "del operator". >[...] >So far, I've found that it's not a Greek or Hebrew letter (as I first >thought it must be), and neither is it (I believe) of Phoenician or >Egyptian origin. If anyone can tell me why nabla is called nabla, >I'll sleep better at night! :-) >[...] From my introductory calculus textbook, _Calculus_, by Howard Anton, third edition, at the bottom of page 995: "The symbol [insert nabla here] (read, "del") is an inverted delta. In older books this symbol is sometimes called a "nabla" because of its similarity in form to an ancient Hebrew ten-stringed harp of that name." I attempted to verify this with some references I have around the house, but I couldn't find anything. Sounds semi-plausible, though. --Travis
yaronf@huji.ac.il (Yaron Farber) (08/21/90)
lowj_ltd@uhura.cc.rochester.edu (John "Travis" Low) writes: >tih@barsoom.nhh.no (Tom Ivar Helbekkmo) writes: >>I've been trying to find out these past couple of days what the origin >>of the name of the character/symbol "nabla" is. Nabla is used (as far >>as I can gather) primarily in mathematics, and is a greek delta turned >>upside down (i.e. a triangle standing on one of its points). >From my introductory calculus textbook, _Calculus_, by Howard Anton, >third edition, at the bottom of page 995: >"The symbol [insert nabla here] (read, "del") is an inverted delta. In >older books this symbol is sometimes called a "nabla" because of its >similarity in form to an ancient Hebrew ten-stringed harp of that name." >--Travis My Webster's 9th Collegiate wouldn't help, which is a shame, but indeed "nevel" is Modern Hebrew for harp (`b' and `v' are related in Semitic languages, including Hebrew) and this name also appears in the Bible. But I don't know how you can prove exactly what instrument it was. -- Yaron Farber TEL: +972-3-282520 BITNET: yaronf@HUJINIX CSNET & INTERNET: yaronf@mush.huji.ac.il Snail: 22 Hissin St., 64284 Tel Aviv, Israel