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*To*: common-lisp@su-ai*Subject*: gaussian rationals*From*: fateman%UCBKIM@Berkeley (Richard Fateman)*Date*: Sun, 05 Jun 1983 15:13:00 -0000

Frankly, complex arithmetic should not be designed by a consensus of Lisp hackers. The difference between mathematical theory and computation is perhaps not clear to Alan, but there is a difference between thinking mathematically and computationally. For example, division by 0 is not defined in a mathematical field. Computationally, division by 0 must be treated SOME way. Similarly, -1 and -1+0*i can be said to be mathematically identical, but that says very little about how to compute with them. In particular, whether sqrt(*) gives an error or not. One view of sqrt(-4) is that it should return -2. The sign of the answer clearly indicates something funny went on. I would propose that rather than vote on complex arithmetic in this forum, real arithmetic only be specified, and allow someone at some later time specify a package for complex.

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