Re: 'monotonic increasing'

Henrik Levkowetz <henrik@levkowetz.com> Fri, 17 February 2006 18:41 UTC

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Date: Fri, 17 Feb 2006 19:41:40 +0100
From: Henrik Levkowetz <henrik@levkowetz.com>
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To: Ken Raeburn <raeburn@MIT.EDU>
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Cc: ietf <ietf@ietf.org>
Subject: Re: 'monotonic increasing'
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Hi Ken,

on 2006-02-17 18:46 Ken Raeburn said the following:
> On Feb 17, 2006, at 11:14, Tom.Petch wrote:
>> Elsewhere - dictionaries, encyclopaedia, text books -  I see it
>> defined so that when applied to a sequence of numbers, then each  
>> number is not
>> less than its predecessor, so that
> 
> That's "non-decreasing".  As far as I've ever heard (math classes as  
> well as CS), a monotonic increasing sequence is one where each  
> element is strictly greater than the previous element.

Tom's definition is also correct.  A "strictly monotonically increasing
sequence" has each term larger than its predecessor, but a "monotonically
increasing sequence" in most definitions has each term equal to or
larger than its predecessor.  However in some contexts "monotonically
increasing" seems to be synonymous with "strictly monotonically increasing",
conforming to your definition.

This is both what I remember from studies a long time ago, and what
seems to be indicated in the online references I checked.

As to IETF usage, I would applaud us using the same definitions
as the rest of the world.


	Henrik




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