From: Han de Bruijn on
David Kastrup wrote:

> Han de Bruijn <Han.deBruijn(a)DTO.TUDelft.NL> writes:
>
>>MoeBlee wrote:
>>
>>>Meanwhile, I'm still fascinated by your inconsistent theory, posted at
>>>your web site, which is:
>>>Z, without axiom of infinity, bu with your axiom: Ax x = {x}.
>>>Would you say what we are to gain from this inconsistent theory?
>>
>>No. But first we repeat the mantra:
>>
>> A little bit of Physics would be NO Idleness in Mathematics
>
> Oh, it is there alright, like a little bit of real life is in a novel
> worth reading.
>
>>It is physically correct that every member of a set is at the same
>>time
>
> You blew it. A "set" is not a physical entity, so there is nothing
> that can be "physically correct" about a set.

So to speak. The more accurate formulation is that a set in mathematics
should be an idealization from something that is called a set in common
speech, say physics in a broad sense. Take that and you will find that
what I've said is correct. I don't say, though, that sets in mainstream
mathematics actually _are_ what they should be, according to the mantra.

>>a _part_ of the set, meaning that a e A ==> a c A , where e stands
>>for membership and c for being a subset. The above axiom that a
>>member of a set cannot physically distinguished from a set which
>>contains only the member - the envelope {} means nothing, physically
>
> The whole set means nothing, physically.

Finite sets can be materialized and _mean_ something, physically. I can
even make music with them. In the thread "Set inclusion and membership"

> Randy Poe wrote:
>
>> Where do you believe set theory comes up in physics?
>
> If you believe that music is physics ... I have an application where set
> theory is employed with the transition of chords. With the chords Am and
> C, for example, only the notes in the symmetric difference Am<>C need to
> be changed (to become Off or On respectively).

And:

>> By the way, I don't think your music idea is valid beyond your
>> trivial example. Show me how it tells me the right chord
>> progression to go from, oh, C Maj to F# Maj to G minor for
>> instance.
>
> Oh well. C Maj = {C,E,G,B} , F# Maj = {F#,A#,C#,F} , G minor = {G,A#,D}
> Hence F# Maj \ C Maj = {F#,A#,C#,F} On , C Maj \ F# Maj = {C,E,G,B} Off.
> (You've defined disjoint sets.) Now wait and listen. Then:
> G minor \ F# Maj = {G,D} On , F# Maj \ G minor = {F#,C#,F} Off.

Han de Bruijn


From: Dik T. Winter on
In article <1122395188.769778.34530(a)z14g2000cwz.googlegroups.com> malbrain(a)yahoo.com writes:
> Dik T. Winter wrote:
> > In article <1122347583.518181.245300(a)g14g2000cwa.googlegroups.com> malbrain(a)yahoo.com writes:
> > >
> > > The C language is defined by the C standard, as defined by ISO. There
> > > are no "unbounded" standard types in the C language. karl m
> >
> > Who is talking about C?
>
> Of the billions of computer systems deployed since the micro-computer
> revolution, the overwhelming majority are programmed with C.

That is not an answer.
--
dik t. winter, cwi, kruislaan 413, 1098 sj amsterdam, nederland, +31205924131
home: bovenover 215, 1025 jn amsterdam, nederland; http://www.cwi.nl/~dik/
From: Dik T. Winter on
In article <MPG.1d5044b418d0c79d989f94(a)newsstand.cit.cornell.edu> Tony Orlow (aeo6) <aeo6(a)cornell.edu> writes:
> Dik T. Winter said:
....
> > Indeed in the dyadic system when all digits are 2 we divide by 2 by
> > replacing each digit by 1. But shifting to the right is *not* the
> > same as (truncating) division by 2. That is only the case if the
> > least significant digit is 2.

(That last 2 should have been 1.)

> That's not true. If each digit place represents a power of the base, then
> shifting everything to the right one digit divides the denoted value of that
> digit by the number base. Here, each place denotes a power of 2, and moving
> all digits to the right one place divides the entire number by two, perhaps
> with remainder.

Lessee. In the dyadic system 8 = "112". Shifting one position to the right
gives "11" = 3. I would not call that dividing by 2.

> To
> declare the set the same size as a proper subset is a lot of what offends
> the sensibilities of anti-Cantorians,

Not all anti-Cantorians. There are also those who state that oo+1 = oo,
which is in essence the same.

> and to declare that this is the case for
> infinite sets, rather than to admit that bijections of themselves do NOT
> prove equal size in that case, is a baffling choice on the part of the
> mathematical community.

Well, bijections provide an excellent way to compare sets, because it is
an equivalence relation, and so they define equivalence classes.

> > The point is, when you allow "infinite" naturals, then those naturals can
> > be put in 1-1 correspondence with the power set of the *finite* naturals.
> > There is no problem with that. But they can not be put in 1-1
> > correspondence with the power set of the enlarged set of naturals.
>
> Why not? The "enlarged set" goes on forever, and the set of subsets goes on
> forever, and can be put into a linear order based on membership of elements,
> which can be seen to correspond with the naturals that go on forever. Where do
> you see a problem?

Pray explain your mapping, it is not clear.
--
dik t. winter, cwi, kruislaan 413, 1098 sj amsterdam, nederland, +31205924131
home: bovenover 215, 1025 jn amsterdam, nederland; http://www.cwi.nl/~dik/
From: David Kastrup on
Han de Bruijn <Han.deBruijn(a)DTO.TUDelft.NL> writes:

> David Kastrup wrote:
>
>> Han de Bruijn <Han.deBruijn(a)DTO.TUDelft.NL> writes:
>>
>>>MoeBlee wrote:
>>>
>>>>Meanwhile, I'm still fascinated by your inconsistent theory, posted at
>>>>your web site, which is:
>>>>Z, without axiom of infinity, bu with your axiom: Ax x = {x}.
>>>>Would you say what we are to gain from this inconsistent theory?
>>>
>>>No. But first we repeat the mantra:
>>>
>>> A little bit of Physics would be NO Idleness in Mathematics
>> Oh, it is there alright, like a little bit of real life is in a
>> novel worth reading.
>>
>>>It is physically correct that every member of a set is at the same
>>>time
>> You blew it. A "set" is not a physical entity, so there is nothing
>> that can be "physically correct" about a set.
>
> So to speak. The more accurate formulation is that a set in
> mathematics should be an idealization from something that is called
> a set in common speech, say physics in a broad sense. Take that and
> you will find that what I've said is correct.

No, take that, and what you said is rubbish. It is the _deciding_
mark of an idealization that it is _not_ identical to what is being
idealized. So an idealization will _never_ be "physically correct".

--
David Kastrup, Kriemhildstr. 15, 44793 Bochum
From: Han de Bruijn on
David Kastrup wrote:

> Han de Bruijn <Han.deBruijn(a)DTO.TUDelft.NL> writes:
>
>
>>David Kastrup wrote:
>>
>>
>>>Han de Bruijn <Han.deBruijn(a)DTO.TUDelft.NL> writes:
>>>
>>>
>>>>MoeBlee wrote:
>>>>
>>>>
>>>>>Meanwhile, I'm still fascinated by your inconsistent theory, posted at
>>>>>your web site, which is:
>>>>>Z, without axiom of infinity, bu with your axiom: Ax x = {x}.
>>>>>Would you say what we are to gain from this inconsistent theory?
>>>>
>>>>No. But first we repeat the mantra:
>>>>
>>>> A little bit of Physics would be NO Idleness in Mathematics
>>>
>>>Oh, it is there alright, like a little bit of real life is in a
>>>novel worth reading.
>>>
>>>
>>>>It is physically correct that every member of a set is at the same
>>>>time
>>>
>>>You blew it. A "set" is not a physical entity, so there is nothing
>>>that can be "physically correct" about a set.
>>
>>So to speak. The more accurate formulation is that a set in
>>mathematics should be an idealization from something that is called
>>a set in common speech, say physics in a broad sense. Take that and
>>you will find that what I've said is correct.
>
>
> No, take that, and what you said is rubbish. It is the _deciding_
> mark of an idealization that it is _not_ identical to what is being
> idealized. So an idealization will _never_ be "physically correct".

You're right. But you don't even try to understand what I mean. Do you?

Han de Bruijn