Re: [r6rs-discuss] Comparison procedures' number of arguments

2008-10-21 Thread leppie
Hi I dont understand all this 'confusion'. Example: monotonically increasing ( 1) should be #f or error, there is no increase, hence no comparison. Logically, how can you ask: - What is the difference? () - What is the difference between a frog? ( frog) Neither of those make any sense.

Re: [r6rs-discuss] Comparison procedures' number of arguments

2008-10-21 Thread Abdulaziz Ghuloum
On Oct 21, 2008, at 8:03 AM, Ken Dickey wrote: Doesn't it make more sense to require existence for comparison? Existence of one ordered pair does not matter much. You need to either prove the existence of a counter example to produce #f, or to prove universality (e.g., with for-all) to

Re: [r6rs-discuss] Comparison procedures' number of arguments

2008-10-21 Thread Ken Dickey
On Tuesday 21 October 2008 05:03:07 Ken Dickey wrote:   1 * x = 1 Apologies. That should certainly be 1 * x = x RWIM [Read What I Mean] -KenD ___ r6rs-discuss mailing list r6rs-discuss@lists.r6rs.org

Re: [r6rs-discuss] Comparison procedures' number of arguments

2008-10-21 Thread Ken Dickey
On Tuesday 21 October 2008 07:42:48 Abdulaziz Ghuloum wrote: On Oct 21, 2008, at 8:03 AM, Ken Dickey wrote: Doesn't it make more sense to require existence for comparison? Existence of one ordered pair does not matter much. You need to either prove the existence of a counter example to

Re: [r6rs-discuss] Comparison procedures' number of arguments

2008-10-21 Thread Abdulaziz Ghuloum
On Oct 21, 2008, at 11:04 AM, Ken Dickey wrote: No. Actually, I'd like a holds-for-all which returns #f as the base case. You can push it down, but you can't escape making these exceptions. Nonrecursive definitions: for-all p? [a_i, ...] = (and (p? a_i) ...) holds-for-all p? [] = #f

Re: [r6rs-discuss] Comparison procedures' number of arguments

2008-10-21 Thread Ken Dickey
On Tuesday 21 October 2008 08:32:12 Abdulaziz Ghuloum wrote: On Oct 21, 2008, at 11:04 AM, Ken Dickey wrote: No. Actually, I'd like a holds-for-all which returns #f as the base case. You can push it down, but you can't escape making these exceptions. The law of the excluded third has a

Re: [r6rs-discuss] Comparison procedures' number of arguments

2008-10-21 Thread Thomas Lord
Ken Dickey wrote: Comparison is taught in kindergarden. Comparison is fundamental. And in algebra. Things I didn't see taught in high school were definitions for relation, transitive relation, reflexive relation, symmetric relation, partial order, total order, and equivalence along with

Re: [r6rs-discuss] Comparison procedures' number of arguments

2008-10-21 Thread John Cowan
Thomas Lord scripsit: For example, you know that if you raise a total ordering of characters to a lexical ordering of strings that the resulting lexical order is a total order. Though not necessarily the correct total order. -- By Elbereth and Luthien the Fair, you shall [EMAIL

Re: [r6rs-discuss] Comparison procedures' number of arguments

2008-10-21 Thread Thomas Lord
Ken Dickey wrote: On Tuesday 21 October 2008 08:32:12 Abdulaziz Ghuloum wrote: On Oct 21, 2008, at 11:04 AM, Ken Dickey wrote: No. Actually, I'd like a holds-for-all which returns #f as the base case. You can push it down, but you can't escape making these exceptions.

Re: [r6rs-discuss] Comparison procedures' number of arguments

2008-10-21 Thread Thomas Lord
John Cowan wrote: Thomas Lord scripsit: For example, you know that if you raise a total ordering of characters to a lexical ordering of strings that the resulting lexical order is a total order. Though not necessarily the correct total order. Yes, well, that's a whole other

Re: [r6rs-discuss] Comparison procedures' number of arguments

2008-10-21 Thread Ken Dickey
On Tuesday 21 October 2008 12:53:32 Thomas Lord wrote: Ken Dickey wrote: Comparison is taught in kindergarden. Comparison is fundamental. And in algebra. Things I didn't see taught in high school were definitions for relation, transitive relation, reflexive relation, symmetric relation,

Re: [r6rs-discuss] Comparison procedures' number of arguments

2008-10-21 Thread Ken Dickey
On Tuesday 21 October 2008 12:53:32 Thomas Lord wrote: Ken Dickey wrote: Can't we just use comparison predicates to compare quantities? A set of binary predicates makes sense to me. The way the word is usually used, the consequent of the conditional should return #t. (You're defining

Re: [r6rs-discuss] Comparison procedures' number of arguments

2008-10-21 Thread Egil Kvaleberg
Ken Dickey wrote: I know (=) = #t looks normal _to you_. But I believe that you are a specialist and I think that you are trying to inject a particular logic into a basic literacy kind of usage. Sorry to disturb an otherwise interesting discussion, but isn't all of this much easier to

Re: [r6rs-discuss] Comparison procedures' number of arguments

2008-10-21 Thread Ken Dickey
On Tuesday 21 October 2008 14:01:16 Egil Kvaleberg wrote: Ken Dickey wrote: I know (=) = #t looks normal _to you_. But I believe that you are a specialist and I think that you are trying to inject a particular logic into a basic literacy kind of usage. Sorry to disturb an otherwise

Re: [r6rs-discuss] +/- nan/inf .0

2008-10-21 Thread Thomas Lord
John Cowan wrote: Thomas Lord scripsit: Asked to compute (= +inf.0 +inf.0) Scheme should dynamically raise the question: Well, what do you mean exactly? Why dynamically? Why isn't static override (i.e. replacing = with a predicate that does what you want) good enough?

Re: [r6rs-discuss] Comparison procedures' number of arguments

2008-10-21 Thread Ken Dickey
On Tuesday 21 October 2008 14:57:19 you wrote: should read:   Ken's definition = a singleton or empty  list is _not_ ordered.   And you should be saying monotonic or sorted as well. Precisely. Something that cannot be compared with cannot be ordered or sorted so cannot be monotonic

Re: [r6rs-discuss] Comparison procedures' number of arguments

2008-10-21 Thread Thomas Lord
Ken Dickey wrote: On Tuesday 21 October 2008 14:57:19 you wrote: should read: Ken's definition = a singleton or empty list is _not_ ordered. And you should be saying monotonic or sorted as well. Precisely. Something that cannot be compared with cannot be ordered or

Re: [r6rs-discuss] Comparison procedures' number of arguments

2008-10-21 Thread Andre van Tonder
On Tue, 21 Oct 2008, Ken Dickey wrote: (sorted? a) = #f (sorted?) = #f I suspect that would come as a nasty surprise to a majority of users of such a predicate. Andre ___ r6rs-discuss mailing list r6rs-discuss@lists.r6rs.org