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*To*: Aubrey Jaffer <agj@x>*Subject*: Re: [Scheme-reports] Numerical example (real? -2.5+0.0i)*From*: Hans Aberg <haberg-1@x>*Date*: Wed, 5 Oct 2011 18:00:52 +0200*Cc*: John Cowan <cowan@x>, scheme-reports@x*In-reply-to*: <20111003020821.A6C798C064A@voluntocracy.org>*References*: <qotei0nf78i.fsf@ruuvi.it.helsinki.fi> <20110815160512.1C1008C0663@voluntocracy.org> <20110815190618.GB31780@mercury.ccil.org> <20111002021320.GB17057@mercury.ccil.org> <20111002030248.B21738C0132@voluntocracy.org> <20111002054800.GE17057@mercury.ccil.org> <20111003020821.A6C798C064A@voluntocracy.org>

On 3 Oct 2011, at 04:08, Aubrey Jaffer wrote: > | > Shouldn't the predicates REAL? and COMPLEX? implement the > | > mathematical semantics for which they are named? > | > | ... There are two reasonable sets of semantics here, and by > | providing two sets of procedures we can support both. By adding an > | "exact-complex" feature, a program that depends on exact complex > | numbers can rely on being run only on an implementation that > | supports them. > > The terms integer, rational, real, and complex are too few to > adequately describe all the possible numeric Scheme types. Rather > than misuse basic mathematical terms, coin new names for the numeric > types which don't match the mathematical types. In math, there are two distinct copies of the integers in play: the ring of integers Z, and the copy of it embedded into the field Q of rational numbers. A similar thing happens with real and complex numbers. One could think of having that model in a computer program. Hans _______________________________________________ Scheme-reports mailing list Scheme-reports@x http://lists.scheme-reports.org/cgi-bin/mailman/listinfo/scheme-reports

**References**:**[Scheme-reports] Numerical example (real? -2.5+0.0i)***From:*Jussi Piitulainen <jpiitula@x>

**Re: [Scheme-reports] Numerical example (real? -2.5+0.0i)***From:*Aubrey Jaffer <agj@x>

**Re: [Scheme-reports] Numerical example (real? -2.5+0.0i)***From:*John Cowan <cowan@x>

**Re: [Scheme-reports] Numerical example (real? -2.5+0.0i)***From:*John Cowan <cowan@x>

**Re: [Scheme-reports] Numerical example (real? -2.5+0.0i)***From:*Aubrey Jaffer <agj@x>

**Re: [Scheme-reports] Numerical example (real? -2.5+0.0i)***From:*John Cowan <cowan@x>

**Re: [Scheme-reports] Numerical example (real? -2.5+0.0i)***From:*Aubrey Jaffer <agj@x>

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