From cbmvax!uunet!math.ucla.edu!jimc Tue Apr 23 21:30:57 1991 Return-Path: From: cbmvax!uunet!math.ucla.edu!jimc Return-Path: Message-Id: <9104231610.AA11318@luna.math.ucla.edu> To: lojban-list@snark.thyrsus.com Cc: cbmvax!snark.thyrsus.com!cowan (John Cowan) Subject: Re: anaphor means what? (was: oops! correction) In-Reply-To: Your message of "Mon, 22 Apr 91 12:17:31 EDT." Date: Tue, 23 Apr 91 09:10:22 -0700 Status: RO > Date: Mon, 22 Apr 91 12:17:31 EDT > To: lojban-list@snark.thyrsus.com > From: cbmvax!snark.thyrsus.com!cowan@uunet.UU.NET (John Cowan) > Subject: Re: oops! correction > Lojban's position on anaphora is that pro-sumti and pro-bridi generally > refer to the same referent as the selected sumti or bridi... > > dei jitfa > This sentence is false. > .i go'i > The previous sentence is false. > .i go'e ra'o > This sentence is false too. > > The first sentence uses the utterance pro-sumti "dei" to refer to itself, > and asserts of itself that it is false. (Presumably, the guaspi version > of this would macroexpand to an infinitely long string.) Gulp (red face...) Fortunately my parser checks for being out of memory. This self-referential business came up before, when I was replicating a selbri into a subordinate clause that modifies it, and it was cut off by a special hack; I didn't think imaginatively enough to realize that legitimate user-supplied self-referential anaphora would have to be handled effectively. In the -gua!spi interpretation, by the time sentences 2 and 3 get hold of sentence 1, sentence 1's anaphora have already been replaced by their antecedents, and so (neglecting minor infinite loops) the same effect is achieved as in Lojban. This relies on the fact that repeated sumti (without anaphora) will have the same referents. Heading off an objection: -gua!spi selbri are assumed to have implicit anaphora for non-mentioned modal cases such as tense, which are substituted when the selbri is digested, and the result of which is copied when the subsequent anaphor is expanded. So the copied sumti / selbri is interpreted in its original context. The advantage of copying words and not referents is this: When you get to the phase of semantic analysis you are going to compute selbri referent sets. It is going to be a whole lot easier if the only thing presented to the semantic analyser is a bunch of selbri. If additionally there are anaphora for about ten different grammatical categories (categories that ought to be transformed away by this point), it makes the semantic analyser much more complicated. Also, when you define an anaphor by copying words, you define it in terms of grammatical structures being defined at or before that point. Whereas if you tell a student "this will represent a copy of the referents ultimately to be computed for this other structure", you are reaching a long way down the process. The student will have just as much trouble understanding your teaching as the semantic analyser program will. Finally: the original motivation of this policy was to support modified anaphora. You hang a modal phrase, or even a "specified description" (sumti on a sumti), on an anaphor and you expect it to replace or supplement the original -- obviously the original words, since it's outrageous to expect referents to be backmapped into symbols that represent them, the modifications to be tacked on, and the symbols reprocessed back into (certainly different) referents. This insight then led me to recognize the general advantage of copying words, not referents. James F. Carter (213) 825-2897 UCLA-Mathnet; 6221 MSA; 405 Hilgard Ave.; Los Angeles, CA, USA 90024-1555 Internet: jimc@math.ucla.edu BITNET: jimc%math.ucla.edu@INTERBIT UUCP:...!{ucsd,ames,ncar,gatech,purdue,rutgers,decvax,uunet}!math.ucla.edu!jimc