From cbmvax!uunet!cuvma.bitnet!LOJBAN Fri Dec 6 12:56:16 1991 Return-Path: Date: Fri Dec 6 12:56:16 1991 Message-Id: <9112061251.AA26583@relay1.UU.NET> Reply-To: cbmvax!uunet!pucc.princeton.edu!C.J.Fine Sender: Lojban list From: CJ FINE Subject: Re: Lack of geometry To: cowan@snark.BITNET Cc: Lojban list In-Reply-To: ; from "snark!cowan" at Nov 27, 91 2:38 pm Status: RO Nice try for going at the geometry, but ... I find several of your proposed lujvo rather flabby - by which I mean yes, they would do, but they don't sound like the result of careful thought. One thing that occurs to me is that many of the words have several meanings in English, and need several different lujvo. > > > triangle cibjantra [three-angle-shape] > > rectangle ganrykurfa [broad-square] > > rhombus kurkro [square-bent] > > polygon so'irkoitra [many-edge-shape] Why is a triangle made of angles but a polygon of edges? Either edge, angle or line would do, but please use them consistently. There were suggestions for these in a JL - either 8 or 11. cibli'i, I think. I find ganrykurfa very impressionistic also - it's equally well a nalganrykurfa. 'unequal square' would be better, or (for many purposes) 'right-angled quadrilateral' (remember a square is a rectangle) And 'kurkro' is not bad for rhombus, but surely 'bent-square' is better. In general, 'equal quadrilateral' is more precise. > > > circle cukla tarmi -- cukla is "circular", tarmi is "shape" > or 'cuktra' in lujvo form > > ellipse ganrycuktra [broad-circular-shape] > > parabola selrerkru [thrown-curve] > because a parabola is the path of a thrown object > > hyperbola bancykemselrerku [beyond-parabola] > or make le'avla: kruvrparabola, kruvrxuperbola. Same objection for 'ellipse'. 'unequal circle?' The metaphor for parabola is the same as the Greek one we use in English, and is assuredly appropriate for some uses - when talking about ballistics, for example. But it seems to me that when we are talking about geometry, it would be preferable to use a geometric characterisation: make a lujvo for '2nd degree curve', and then characterise it as 'open'? .iacu'i (In some contexts it could be a 'parallel-slope ke cone-cut curve'. Do we have expression for these?) Hyperbola, similarly, but there the Greek metaphor is less comprehensible to most people. 'Ellipse', by the way is the same metaphor: 'falling away', ie falling short of the parabola. > > > axis jendu?? > No, that's a physical object (axle); try "selcarna", > the rotated-on thing. Nice catch. Notice that an axis can be to do with symmetry as well as rotation. > > diameter nizganra [quantity-of-wideness] > > radius xabykemnizganra [half-diameter] > or make le'avla: cmacnradi Again, there are two different diameters: 'nizganra' will do for the diameter of a general closed curve; but I would prefer something more precise for the diameter of a circle. 'across-measure'? Notice that in mathematical writing we sometimes use 'diameter' to mean a line across rather than its measure, and this is different again. To me, being half the diameter is an incidental property of the radius: something like 'edge distance' is better. co'omi'e kolin