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Polishing up II

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Jack

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Jun 25, 2012, 6:33:14 AM6/25/12
to
Once again I have got this issue of wanting to say two things in one (and
ideally I want to be able to reference the assertion, all in one), namely
that f(x)/g(x) is strictly decreasing and approaches 1.
Currently I am writing
'f(x)/g(x) ~ 1, the quotient being strictly decreasing'
or
'lim_(x-->oo) f(x)/g(x) = 1
with f(x)/g(x) >1'.
I don't know if this is the best phrasing; I have read that the notation I
am using here is known as asymptotic notation but my functions are
monotonic -- the curves they produce are smooth. Any views?

Also, I have changed the sentence
<<For x<y in mathbb{N}, [x,y] = {n n mathbb{N} : x <= n <= y} >>
given to me by Paul, to <<all intervals are be taken to be intervals of
integers>>. I wonder whether this is OK, given that Paul's version might be
seen to be doing something more, namely indicating that the square brackets
denote endpoints. Is the open/-closed-bounded notation using round and
square brackets respectively, sufficiently standard that I don't need to
worry?

With thanks.


William Elliot

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Jun 25, 2012, 7:03:53 AM6/25/12
to
On Mon, 25 Jun 2012, Jack wrote:

> Once again I have got this issue of wanting to say two things in one (and
> ideally I want to be able to reference the assertion, all in one), namely
> that f(x)/g(x) is strictly decreasing and approaches 1.

f(x) strictly decreases to 1 as x -> oo.

> Currently I am writing
> 'f(x)/g(x) ~ 1, the quotient being strictly decreasing'

I suppose. So when defining f(x) ~ r, don't be glib,
spell it all out. f is a monotonically decreasing function
with lim(x->oo) f(x) = r.

> or
> 'lim_(x-->oo) f(x)/g(x) = 1
> with f(x)/g(x) >1'.

No, that's saying something different.

> I don't know if this is the best phrasing; I have read that the notation I
> am using here is known as asymptotic notation but my functions are
> monotonic -- the curves they produce are smooth. Any views?

Yes, asymptotic and monotone are different.

> Also, I have changed the sentence <<For x<y in mathbb{N}, [x,y] = {n n
> mathbb{N} : x <= n <= y} >> given to me by Paul, to <<all intervals are
> be taken to be intervals of integers>>. I wonder whether this is OK,
> given that Paul's version might be seen to be doing something more,
> namely indicating that the square brackets denote endpoints. Is the
> open/-closed-bounded notation using round and square brackets
> respectively, sufficiently standard that I don't need to worry?

{n n > mathbb{N} : x <= n <= y}

is a typo and skip the TeX.

In Europe, they use ]a,b[ for (a,b).

When restriced to integers only
one is needed for (a,b) = [a-1, b+1].

Jack

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Jun 25, 2012, 7:15:44 AM6/25/12
to

"William Elliot" <ma...@panix.com> wrote in message
news:Pine.NEB.4.64.12...@panix3.panix.com...
> On Mon, 25 Jun 2012, Jack wrote:
>
>> Once again I have got this issue of wanting to say two things in one (and
>> ideally I want to be able to reference the assertion, all in one), namely
>> that f(x)/g(x) is strictly decreasing and approaches 1.
>
> f(x) strictly decreases to 1 as x -> oo.
>
>> Currently I am writing
>> 'f(x)/g(x) ~ 1, the quotient being strictly decreasing'
>
> I suppose. So when defining f(x) ~ r, don't be glib,
> spell it all out. f is a monotonically decreasing function
> with lim(x->oo) f(x) = r.

Or f(x)/g(x) is a monotonically decreasing function with <...>?


>
>> or
>> 'lim_(x-->oo) f(x)/g(x) = 1
>> with f(x)/g(x) >1'.
>
> No, that's saying something different.

It doesn't state that it's strictly decreasing can I take it that what I
write above is not in any way unacceptable? (I can see it almost looks like
a contradiction when both the "= 1" and the " >1" are used.)

>> I don't know if this is the best phrasing; I have read that the notation
>> I
>> am using here is known as asymptotic notation but my functions are
>> monotonic -- the curves they produce are smooth. Any views?
>
> Yes, asymptotic and monotone are different.
>

Are you saying that, with the monotonic functions I am referring to, the use
of '~', which I'm told is asymptotic notation, is not right? (Or not ideal?)

>> Also, I have changed the sentence <<For x<y in mathbb{N}, [x,y] = {n n
>> mathbb{N} : x <= n <= y} >> given to me by Paul, to <<all intervals are
>> be taken to be intervals of integers>>. I wonder whether this is OK,
>> given that Paul's version might be seen to be doing something more,
>> namely indicating that the square brackets denote endpoints. Is the
>> open/-closed-bounded notation using round and square brackets
>> respectively, sufficiently standard that I don't need to worry?
>
> {n n > mathbb{N} : x <= n <= y}
>
> is a typo and skip the TeX.
>
> In Europe, they use ]a,b[ for (a,b).
>
> When restriced to integers only
> one is needed for (a,b) = [a-1, b+1].

You're sayng I'm best advised to avoid using open-bounded notation? That's a
nuissance as it'll mean some of my equations won't fit on the line.
It sounds as though you're also saying that I *do* need to spell out in my
intro that square brackets denote closed-boundedness at an endpoint, and
round brackets open-boundedness (assuming I do indeed use round brackets).
With thanks.



Jack

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Jun 25, 2012, 7:19:39 AM6/25/12
to

"William Elliot" <ma...@panix.com> wrote in message
news:Pine.NEB.4.64.12...@panix3.panix.com...
> On Mon, 25 Jun 2012, Jack wrote:
>
>> Once again I have got this issue of wanting to say two things in one (and
>> ideally I want to be able to reference the assertion, all in one), namely
>> that f(x)/g(x) is strictly decreasing and approaches 1.
>
> f(x) strictly decreases to 1 as x -> oo.
>
>> Currently I am writing
>> 'f(x)/g(x) ~ 1, the quotient being strictly decreasing'
>
> I suppose. So when defining f(x) ~ r, don't be glib,
> spell it all out. f is a monotonically decreasing function
> with lim(x->oo) f(x) = r.

BTW isn't it -- at least in one sense -- stronger to say 'strictly
decreasing' than 'monotonically decreasing'? Ideally I would like to say
both.


Frederick Williams

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Jun 25, 2012, 11:48:00 AM6/25/12
to
Jack wrote:
>
> Once again I have got this issue of wanting to say two things in one (and
> ideally I want to be able to reference the assertion, all in one), namely
> that f(x)/g(x) is strictly decreasing and approaches 1.
> Currently I am writing
> 'f(x)/g(x) ~ 1, the quotient being strictly decreasing'
> or
> 'lim_(x-->oo) f(x)/g(x) = 1
> with f(x)/g(x) >1'.

You could write 'f(x)/g(x) diagonal arrow pointing from top left to
bottom right 1 as x --> oo'; which is read as 'f(x)/g(x) tends to one
from above as x tends to infinity.' The arrow in question is
$\searrow$.

> I don't know if this is the best phrasing; I have read that the notation I
> am using here is known as asymptotic notation but my functions are
> monotonic -- the curves they produce are smooth. Any views?

You write as if you think that asymptotic notation cannot be used for
functions that are monotonic or smooth. That isn't so.

> Also, I have changed the sentence
> <<For x<y in mathbb{N}, [x,y] = {n n mathbb{N} : x <= n <= y} >>
> given to me by Paul, to <<all intervals are be taken to be intervals of
> integers>>. I wonder whether this is OK, given that Paul's version might be
> seen to be doing something more, namely indicating that the square brackets
> denote endpoints. Is the open/-closed-bounded notation using round and
> square brackets respectively, sufficiently standard that I don't need to
> worry?

One short sentence takes care of [n,m], [n,m), (n,m] and (n,m). That
sentence is 'all intervals are intervals of natural numbers.'

--
The animated figures stand
Adorning every public street
And seem to breathe in stone, or
Move their marble feet.

Frederick Williams

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Jun 25, 2012, 11:52:29 AM6/25/12
to
Jack wrote:

>
> Or f(x)/g(x) is a monotonically decreasing function with <...>?

'f(x)/g(x) decreases monotonically to L as x increases' is ok.

> [...] (I can see it almost looks like
> a contradiction when both the "= 1" and the " >1" are used.)

'limit of blah = L' doesn't require blah to ever equal L.

>
> You're sayng I'm best advised to avoid using open-bounded notation?

Just take Paul's advice that you mention in your OP.

Frederick Williams

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Jun 25, 2012, 11:54:09 AM6/25/12
to
Jack wrote:

>
> BTW isn't it -- at least in one sense -- stronger to say 'strictly
> decreasing' than 'monotonically decreasing'? Ideally I would like to say
> both.

If one _is_ stronger than the other, just state the stronger. The
definitions should reveal which (if either) is the stronger.

William Elliot

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Jun 25, 2012, 10:30:59 PM6/25/12
to
On Mon, 25 Jun 2012, Jack wrote:

>
> "William Elliot" <ma...@panix.com> wrote in message
> news:Pine.NEB.4.64.12...@panix3.panix.com...
> > On Mon, 25 Jun 2012, Jack wrote:
> >
> >> Once again I have got this issue of wanting to say two things in one (and
> >> ideally I want to be able to reference the assertion, all in one), namely
> >> that f(x)/g(x) is strictly decreasing and approaches 1.
> >
> > f(x) strictly decreases to 1 as x -> oo.
> >
> >> Currently I am writing
> >> 'f(x)/g(x) ~ 1, the quotient being strictly decreasing'
> >
> > I suppose. So when defining f(x) ~ r, don't be glib,
> > spell it all out. f is a monotonically decreasing function
> > with lim(x->oo) f(x) = r.
>
Since you've pointed out that ~ is used for "asymototic to",
don't use it for the above definition. Perhaps you could
write "f(x) down to r" for the defintion which could be
rendered as a one space down arrow in TeX, but don't
use it here.

Jack

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Jun 26, 2012, 5:50:29 AM6/26/12
to
>> You're sayng I'm best advised to avoid using open-bounded notation?
>
> Just take Paul's advice that you mention in your OP.


The only thing is that when I go on to say 'let I be an interval', the idea
that I is an interval of integers is not covered by Paul's sentence; he
later advised me that it wasn't.
When you say
"One short sentence takes care of [n,m], [n,m), (n,m] and (n,m). That
sentence is 'all intervals are intervals of natural numbers.'" this is what
I have got now except that I say 'integers'. Am still concerned that if I
say 'let [x,y] be an interval' it might not necessarily be assumed that x <=
y.
I think, due to the ambiguity of the use of round brackets (eg. with their
also beig used for ordered pairs) I'll go for the [x+1,y], [x,y-1] option,
unless you object.

Cheers.



Jack

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Jun 26, 2012, 5:53:26 AM6/26/12
to

"William Elliot" <ma...@panix.com> wrote in message
news:Pine.NEB.4.64.12...@panix2.panix.com...
> On Mon, 25 Jun 2012, Jack wrote:
>
>>
>> "William Elliot" <ma...@panix.com> wrote in message
>> news:Pine.NEB.4.64.12...@panix3.panix.com...
>> > On Mon, 25 Jun 2012, Jack wrote:
>> >
>> >> Once again I have got this issue of wanting to say two things in one
>> >> (and
>> >> ideally I want to be able to reference the assertion, all in one),
>> >> namely
>> >> that f(x)/g(x) is strictly decreasing and approaches 1.
>> >
>> > f(x) strictly decreases to 1 as x -> oo.
>> >
>> >> Currently I am writing
>> >> 'f(x)/g(x) ~ 1, the quotient being strictly decreasing'
>> >
>> > I suppose. So when defining f(x) ~ r, don't be glib,
>> > spell it all out. f is a monotonically decreasing function
>> > with lim(x->oo) f(x) = r.
>>
> Since you've pointed out that ~ is used for "asymototic to",
> don't use it for the above definition.

It's not a definition, but a result. I am just rather confused that the ~
sign is said to be asymptotic notation. If, as Frederick says, it can also
be used for monotonic functions, then I'm happy with that.


Jack

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Jun 26, 2012, 5:58:50 AM6/26/12
to

"William Elliot" <ma...@panix.com> wrote in message
news:Pine.NEB.4.64.12...@panix3.panix.com...
> On Mon, 25 Jun 2012, Jack wrote:
>
>> Once again I have got this issue of wanting to say two things in one (and
>> ideally I want to be able to reference the assertion, all in one), namely
>> that f(x)/g(x) is strictly decreasing and approaches 1.
>
> f(x) strictly decreases to 1 as x -> oo.
>
>> Currently I am writing
>> 'f(x)/g(x) ~ 1, the quotient being strictly decreasing'
>
> I suppose. So when defining f(x) ~ r, don't be glib,
> spell it all out. f is a monotonically decreasing function
> with lim(x->oo) f(x) = r.

Would you object to my using the term 'converges to'?
I am irked by the mixing of symbology with wording.
I write

"f(x) /g(x) ~ 1 (1)

and is strictly decreasing". Perhaps I'll try that downward-pointing arrow.


Jack

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Jun 26, 2012, 6:06:22 AM6/26/12
to

"Frederick Williams" <freddyw...@btinternet.com> wrote in message
news:4FE8882F...@btinternet.com...
> Jack wrote:
>>
>> Once again I have got this issue of wanting to say two things in one (and
>> ideally I want to be able to reference the assertion, all in one), namely
>> that f(x)/g(x) is strictly decreasing and approaches 1.
>> Currently I am writing
>> 'f(x)/g(x) ~ 1, the quotient being strictly decreasing'
>> or
>> 'lim_(x-->oo) f(x)/g(x) = 1
>> with f(x)/g(x) >1'.
>
> You could write 'f(x)/g(x) diagonal arrow pointing from top left to
> bottom right 1 as x --> oo'; which is read as 'f(x)/g(x) tends to one
> from above as x tends to infinity.' The arrow in question is
> $\searrow$.
>

Does that arrow imply that the approach is *strictly* from above?
So if I was talking of an upward approach, would it be $\nwarrow$?
Still seems to be no way to overcome the clumsiness of spelling out
'f(x)/g(x) \searrow 1 is a monotonic convergence'.


Jack

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Jun 26, 2012, 6:30:57 AM6/26/12
to

"Jack" <no1em...@hotmail.com> wrote in message
news:xQfGr.351877$pD7....@fx21.am4...
>
> "Frederick Williams" <freddyw...@btinternet.com> wrote in message
> news:4FE8882F...@btinternet.com...
>> Jack wrote:
>>>
>>> Once again I have got this issue of wanting to say two things in one
>>> (and
>>> ideally I want to be able to reference the assertion, all in one),
>>> namely
>>> that f(x)/g(x) is strictly decreasing and approaches 1.
>>> Currently I am writing
>>> 'f(x)/g(x) ~ 1, the quotient being strictly decreasing'
>>> or
>>> 'lim_(x-->oo) f(x)/g(x) = 1
>>> with f(x)/g(x) >1'.
>>
>> You could write 'f(x)/g(x) diagonal arrow pointing from top left to
>> bottom right 1 as x --> oo'; which is read as 'f(x)/g(x) tends to one
>> from above as x tends to infinity.' The arrow in question is
>> $\searrow$.
>>
>
> Does that arrow imply that the approach is *strictly* from above?
> So if I was talking of an upward approach, would it be $\nwarrow$?
>
Ah, of course, it would be $\nearrow$!


Jack

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Jun 26, 2012, 6:32:31 AM6/26/12
to

"Jack" <no1em...@hotmail.com> wrote in message
news:tJfGr.304511$9s1.2...@fx31.am4...
Now I've writtem

"f(x)/g(x) \searrow 1

is a strictly decreasing approach."

Sound OK?


Jack

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Jun 26, 2012, 6:34:00 AM6/26/12
to

"Jack" <no1em...@hotmail.com> wrote in message
news:FBfGr.586673$kS.3...@fx17.am4...
I've now got
"Throughout this paper, |N will be the set of non-negative integers and all
intervals are to be taken to be nonempty subsets, [x,y], of |N".
( |N is a script N).
Does that sound OK?
Cheers.


Frederick Williams

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Jun 26, 2012, 8:59:30 AM6/26/12
to
Jack wrote:
>
> [...] Am still concerned that if I
> say 'let [x,y] be an interval' it might not necessarily be assumed that x <=
> y.

It must be, if not-(x<=y) then [x,y] wouldn't be an interval.

> I think, due to the ambiguity of the use of round brackets (eg. with their
> also beig used for ordered pairs) I'll go for the [x+1,y], [x,y-1] option,
> unless you object.

I don't object at all. Other possibilities are: ]x,y[ for (x,y), and,
if you use (x,y) for an ordered pair, use <x,y> for the ordered pair
instead and use (x,y) for the open interval.

Frederick Williams

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Jun 26, 2012, 9:01:56 AM6/26/12
to
Jack wrote:
>
>
> "Throughout this paper, |N will be the set of non-negative integers and all
> intervals are to be taken to be nonempty subsets, [x,y], of |N".

I'd omit ", [x,y],". I thought some of your intervals had one or more
open end-points. If not, what's the worry?

> ( |N is a script N).

|N should be a blackboard bold N. Script is something else.

Frederick Williams

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Jun 26, 2012, 9:03:51 AM6/26/12
to
Jack wrote:

>
> It's not a definition, but a result. I am just rather confused that the ~
> sign is said to be asymptotic notation. If, as Frederick says, it can also
> be used for monotonic functions, then I'm happy with that.

What are you saying I have said? I hope all I said in connection with
this is that if two functions are asymptotic to one another, they can be
monotonic.

Frederick Williams

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Jun 26, 2012, 9:08:27 AM6/26/12
to
Jack wrote:
>
> "Frederick Williams" <freddyw...@btinternet.com> wrote in message
> news:4FE8882F...@btinternet.com...
> > Jack wrote:
> >>
> >> Once again I have got this issue of wanting to say two things in one (and
> >> ideally I want to be able to reference the assertion, all in one), namely
> >> that f(x)/g(x) is strictly decreasing and approaches 1.
> >> Currently I am writing
> >> 'f(x)/g(x) ~ 1, the quotient being strictly decreasing'
> >> or
> >> 'lim_(x-->oo) f(x)/g(x) = 1
> >> with f(x)/g(x) >1'.
> >
> > You could write 'f(x)/g(x) diagonal arrow pointing from top left to
> > bottom right 1 as x --> oo'; which is read as 'f(x)/g(x) tends to one
> > from above as x tends to infinity.' The arrow in question is
> > $\searrow$.
> >
>
> Does that arrow imply that the approach is *strictly* from above?

I don't know what that means.

> So if I was talking of an upward approach, would it be $\nwarrow$?
> Still seems to be no way to overcome the clumsiness of spelling out
> 'f(x)/g(x) \searrow 1 is a monotonic convergence'.

Why not say 'f(x)/g(x) decreases to 1 as x --> oo'. If what x is doing
is obvious, you can just write 'f/g decreases to 1'.

William Elliot mentions the down-pointing arrow (not sloping) that too
is ok.

Jack

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Jun 26, 2012, 12:28:44 PM6/26/12
to

"Frederick Williams" <freddyw...@btinternet.com> wrote in message
news:4FE9B2C4...@btinternet.com...
> Jack wrote:
>>
>>
>> "Throughout this paper, |N will be the set of non-negative integers and
>> all
>> intervals are to be taken to be nonempty subsets, [x,y], of |N".
>
> I'd omit ", [x,y],".

Have changed them all to closed.
I thought that [x ,y] would be a useful inclusion because I might be asking
the reader to ditch the very concept of an interval and instead just think
of any old subset of |N whenever I say 'interval'.


Jack

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Jun 26, 2012, 12:35:35 PM6/26/12
to
>> > You could write 'f(x)/g(x) diagonal arrow pointing from top left to
>> > bottom right 1 as x --> oo'; which is read as 'f(x)/g(x) tends to one
>> > from above as x tends to infinity.' The arrow in question is
>> > $\searrow$.
>> >
>>
>> Does that arrow imply that the approach is *strictly* from above?
>
> I don't know what that means.
>

I meant that it never dips beneath the value it converges to.


Jack

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Jun 26, 2012, 12:39:25 PM6/26/12
to
> You could write 'f(x)/g(x) diagonal arrow pointing from top left to
> bottom right 1 as x --> oo'; which is read as 'f(x)/g(x) tends to one
> from above as x tends to infinity.'

Does this entirely preclude that for some x,

f(x)/g(x) <= f(x+1)/g(x+1)?


Frederick Williams

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Jun 26, 2012, 12:58:22 PM6/26/12
to
Jack wrote:

> I thought that [x ,y] would be a useful inclusion because I might be asking
> the reader to ditch the very concept of an interval and instead just think
> of any old subset of |N whenever I say 'interval'.

Oh, don't do that. If you mean 'subset of |N' then that's what you
should say. 'Interval' is entirely different.

Jack

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Jun 26, 2012, 1:05:11 PM6/26/12
to

"Frederick Williams" <freddyw...@btinternet.com> wrote in message
news:4FE9EA2E...@btinternet.com...
> Jack wrote:
>
>> I thought that [x ,y] would be a useful inclusion because I might be
>> asking
>> the reader to ditch the very concept of an interval and instead just
>> think
>> of any old subset of |N whenever I say 'interval'.
>
> Oh, don't do that. If you mean 'subset of |N' then that's what you
> should say. 'Interval' is entirely different.
>

Yeh I know but the reader might think I am sufficiently eccentric as to be
going about changing the idea of what is meant by 'interval', which of
course I am not :-).


Frederick Williams

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Jun 26, 2012, 1:20:28 PM6/26/12
to
No, I don't think it does. You could say 'f(x)/g(x) decreases
monotonically to 1 as x -> oo'.

Frederick Williams

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Jun 26, 2012, 1:21:26 PM6/26/12
to
Then say f/g decreases monotonically to 1.

Jack

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Jun 26, 2012, 1:35:19 PM6/26/12
to

"Frederick Williams" <freddyw...@btinternet.com> wrote in message
news:4FE9EF96...@btinternet.com...
> Jack wrote:
>>
>> >> > You could write 'f(x)/g(x) diagonal arrow pointing from top left to
>> >> > bottom right 1 as x --> oo'; which is read as 'f(x)/g(x) tends to
>> >> > one
>> >> > from above as x tends to infinity.' The arrow in question is
>> >> > $\searrow$.
>> >> >
>> >>
>> >> Does that arrow imply that the approach is *strictly* from above?
>> >
>> > I don't know what that means.
>> >
>>
>> I meant that it never dips beneath the value it converges to.
>
> Then say f/g decreases monotonically to 1.

So by the use of \searrow, it *can* dip beneath? Oh, no!
I want say more than just that it's monotonic; I want to say f/g is
*strictly* decreasing to 1; and I really want to be able to say it using
symbols instead of words -- at least as far as possible.


Jack

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Jun 26, 2012, 1:39:19 PM6/26/12
to

"Frederick Williams" <freddyw...@btinternet.com> wrote in message
news:4FE9EF5C...@btinternet.com...
> Jack wrote:
>>
>> > You could write 'f(x)/g(x) diagonal arrow pointing from top left to
>> > bottom right 1 as x --> oo'; which is read as 'f(x)/g(x) tends to one
>> > from above as x tends to infinity.'
>>
>> Does this entirely preclude that for some x,
>>
>> f(x)/g(x) <= f(x+1)/g(x+1)?
>
> No, I don't think it does. You could say 'f(x)/g(x) decreases
> monotonically to 1 as x -> oo'.
>

I think I am going to have to say

f(x)/g(x) ~ 1

is a strictly and monotonically decreasing approach. Or

f(x)/g(x) ~ 1

is a strictly decreasing approach.

Are they OK?


Frederick Williams

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Jun 26, 2012, 1:41:28 PM6/26/12
to
Jack wrote:
>
> [...] I want to say f/g is
> *strictly* decreasing to 1; and I really want to be able to say it using
> symbols instead of words -- at least as far as possible.

Why?

Frederick Williams

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Jun 26, 2012, 1:46:01 PM6/26/12
to
I don't get 'approach'. Such-and-such approaches so-and-so.

Jack

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Jun 26, 2012, 2:21:45 PM6/26/12
to

"Frederick Williams" <freddyw...@btinternet.com> wrote in message
news:4FE9F448...@btinternet.com...
> Jack wrote:
>>
>> [...] I want to say f/g is
>> *strictly* decreasing to 1; and I really want to be able to say it using
>> symbols instead of words -- at least as far as possible.
>
> Why?

Again, it's because I can't find a way of referencing the expressions -- I
mean the whole concept of what is happening in the convergence -- that
doesn't look awkward. I can't just say 'Then it follows by that bit on the
middle of page 15, that....'


Jack

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Jun 26, 2012, 2:24:31 PM6/26/12
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"Frederick Williams" <freddyw...@btinternet.com> wrote in message
news:4FE9F559...@btinternet.com...
> Jack wrote:
>>
>> "Frederick Williams" <freddyw...@btinternet.com> wrote in message
>> news:4FE9EF5C...@btinternet.com...
>> > Jack wrote:
>> >>
>> >> > You could write 'f(x)/g(x) diagonal arrow pointing from top left to
>> >> > bottom right 1 as x --> oo'; which is read as 'f(x)/g(x) tends to
>> >> > one
>> >> > from above as x tends to infinity.'
>> >>
>> >> Does this entirely preclude that for some x,
>> >>
>> >> f(x)/g(x) <= f(x+1)/g(x+1)?
>> >
>> > No, I don't think it does. You could say 'f(x)/g(x) decreases
>> > monotonically to 1 as x -> oo'.
>> >
>>
>> I think I am going to have to say
>>
>> f(x)/g(x) ~ 1
>>
>> is a strictly and monotonically decreasing approach. Or
>>
>> f(x)/g(x) ~ 1
>>
>> is a strictly decreasing approach.
>>
>> Are they OK?
>
> I don't get 'approach'. Such-and-such approaches so-and-so.

I thught it would be obvious that it's to one. Perhaps I should revert to
the term 'convergence' instead? But then the preceding 'decreasing' won't
look right.
Jeeez, I can't believe there is no standard way to say the simple things I
am trying to say!


Frederick Williams

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Jun 26, 2012, 2:25:58 PM6/26/12
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You ought to be able to label plain English just as you can formulae.

Frederick Williams

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Jun 26, 2012, 2:27:27 PM6/26/12
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Jack wrote:

> Jeeez, I can't believe there is no standard way to say the simple things I
> am trying to say!

As I suggested: 'f(x)/g(x) decreases monotonically to 1 as x -> oo'.

Jack

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Jun 26, 2012, 2:46:10 PM6/26/12
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"Frederick Williams" <freddyw...@btinternet.com> wrote in message
news:4FE9FF0F...@btinternet.com...
> Jack wrote:
>
>> Jeeez, I can't believe there is no standard way to say the simple things
>> I
>> am trying to say!
>
> As I suggested: 'f(x)/g(x) decreases monotonically to 1 as x -> oo'.
>

Yeh but it's not just monotonic, it's *strictly decreasing*.


Frederick Williams

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Jun 26, 2012, 3:11:48 PM6/26/12
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f(x)/g(x) decreases strictly to 1 as x -> oo.

Jack

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Jun 26, 2012, 3:43:10 PM6/26/12
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"Frederick Williams" <freddyw...@btinternet.com> wrote in message
news:4FEA0974...@btinternet.com...
> Jack wrote:
>>
>> "Frederick Williams" <freddyw...@btinternet.com> wrote in message
>> news:4FE9FF0F...@btinternet.com...
>> > Jack wrote:
>> >
>> >> Jeeez, I can't believe there is no standard way to say the simple
>> >> things
>> >> I
>> >> am trying to say!
>> >
>> > As I suggested: 'f(x)/g(x) decreases monotonically to 1 as x -> oo'.
>> >
>>
>> Yeh but it's not just monotonic, it's *strictly decreasing*.
>
> f(x)/g(x) decreases strictly to 1 as x -> oo.
>

Or maybe f(x)/g(x) is strictly decreasing to 1?
Are you sure I can just stick a label against this, in the middle of a load
of text?


Frederick Williams

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Jun 26, 2012, 3:53:12 PM6/26/12
to
Jack wrote:
>
> "Frederick Williams" <freddyw...@btinternet.com> wrote in message
> news:4FEA0974...@btinternet.com...
> > Jack wrote:
> >>
> >> "Frederick Williams" <freddyw...@btinternet.com> wrote in message
> >> news:4FE9FF0F...@btinternet.com...
> >> > Jack wrote:
> >> >
> >> >> Jeeez, I can't believe there is no standard way to say the simple
> >> >> things
> >> >> I
> >> >> am trying to say!
> >> >
> >> > As I suggested: 'f(x)/g(x) decreases monotonically to 1 as x -> oo'.
> >> >
> >>
> >> Yeh but it's not just monotonic, it's *strictly decreasing*.
> >
> > f(x)/g(x) decreases strictly to 1 as x -> oo.
> >
>
> Or maybe f(x)/g(x) is strictly decreasing to 1?

If it's clear what x is doing.

> Are you sure I can just stick a label against this, in the middle of a load
> of text?

Yes.

William Elliot

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Jun 26, 2012, 9:51:35 PM6/26/12
to
On Tue, 26 Jun 2012, Jack wrote:
> "Jack" <no1em...@hotmail.com> wrote in message
> >
> > Would you object to my using the term 'converges to'?
> > I am irked by the mixing of symbology with wording.
> > I write
> >
> > "f(x) /g(x) ~ 1 (1)
> >
> > and is strictly decreasing". Perhaps I'll try that downward-pointing
> > arrow.
>
> Now I've written
>
> "f(x)/g(x) searrow 1
>
> is a strictly decreasing approach."
>
> Sound OK?
>
No, it stinks for being too terse. Use some words, verbal cheap skate.
Define "f(x) down to r" as "f(x) is strictly decreasing and lim(x->oo) = r.
Furthermore, don't use TeX in this newsgroup, it's not designed for it.

William Elliot

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Jun 26, 2012, 9:54:14 PM6/26/12
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On Tue, 26 Jun 2012, Jack wrote:

"Tends to one from above" needs defining.

Jack

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Jun 28, 2012, 11:44:51 AM6/28/12
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>> Are you sure I can just stick a label against this, in the middle of a
>> load
>> of text?
>
> Yes.

How would I do this? If I just put '(18)' as text, it doesn't get recognised
among the system's numbered equations.
And \label{18} doesn't seem to work outside an equation environment.

I can't say I much like the look of the label at the end of
"... so f(x)/g(x) is strictly and monotonically decreasing to one (18)." but
if you say it's OK I'll go with it.

Thanks.


Jussi Piitulainen

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Jun 28, 2012, 12:28:58 PM6/28/12
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A usual way to label statements for further reference is to set them
aside as numbered theorems, lemmas, conjectures, propositions and
whatever. LaTeX has the means to set statements aside this way, number
them automatically just like it does for equations, with the ability
to refer to them with a symbolic label that is then replaced with the
actual number in the final document, just like with equations.

On to agonize about whether they should be called theorems or
propositions and how deep a thought needs to be before it can be so
labelled at all and when if ever it is appropriate to use words
instead of symbols, and is it really acceptable to set the theorem in
italics, and should the numbering be tied to section or chapter
numbers or not, and what if there is only one theorem in the whole
paper, should it still be numbered? (Do relax some.)

\nonstopmode\documentclass{article}
\newtheorem{thinko}{Thinko}
\begin{document}
(Assume enough material here that the wording of the following thinko
can be understood by the diligent follower.)
\begin{thinko}[the descent from above] Let $f$ and $g$ be mutually
discreet in an ordinary way. Then $f(x)/g(x)$ decreases to $1$
strictly monotonically and most probably without fail as $x$
increases without bound. \label{descent}
\end{thinko}
(assume much stream of consciousness here) by reference to Thinko
\ref{descent} here the labeling of thinkoes for later reference is
hereby demonstrated.
\end{document}

(You need not be so heavy-handed, but you seem to want something like
that. There are books that are essentially a sequence of such labeled
and numbered thoughts. Then there are other books that never use them,
and yet others that label the few central points in them.)
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