It seems that the cunning policy: "It is better to be vague and partly correct than to be precise and completely wrong" is applied particularly to coordinate geometry form the very beginning. It seems that even among mathematicians there is a difference of opinion on the following fundamental issues: (1) Whether a point occupoies space or does not occupy space. (2) Does a point specify only 'location' and not a number? (3) Whether each point has to represent the same number OR a point can represent any number from 0 to infinity, e.g. any value of TanA. (4) Whether a line becomes contiguous/continuous if we ADD points to a line one AFTER another (assign value of X, then calculate the value of Y and finally place the point on its appropriate position) or it requires a different condition.
> It seems that the cunning policy: "It is better to be vague and partly > correct than to be precise and completely wrong" is applied > particularly to coordinate geometry form the very beginning. It seems > that even among mathematicians there is a difference of opinion on the > following fundamental issues: (1) Whether a point occupoies space or > does not occupy space. (2) Does a point specify only 'location' and > not a number? (3) Whether each point has to represent the same number > OR a point can represent any number from 0 to infinity, e.g. any > value of TanA. (4) Whether a line becomes contiguous/continuous if we > ADD points to a line one AFTER another (assign value of X, then > calculate the value of Y and finally place the point on its > appropriate position) or it requires a different condition.
(1) It occupies a pinpoint. (2) It's there. (3) Yes you can count points. (4) Continuous lines have all the little porous pores filled.
"Philosophy, the science and art of antiquated quibbling." -- WE
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> It seems that the cunning policy: "It is better to be vague and partly > correct than to be precise and completely wrong" is applied > particularly to coordinate geometry form the very beginning. It seems > that even among mathematicians there is a difference of opinion on the > following fundamental issues: (1) Whether a point occupoies space or > does not occupy space.
[snip]
You have made your point that you know nothing. Rather than continue eructating amidst thinking people who loathe you, why don't you infest religious newsgroups and delite your peer group of loud morons spewing revelation and inerrancy?
-- Uncle Al http://www.mazepath.com/uncleal/ (Toxic URL! Unsafe for children and most mammals) "Quis custodiet ipsos custodes?" The Net!
> > It seems that the cunning policy: "It is better to be vague and partly > > correct than to be precise and completely wrong" is applied > > particularly to coordinate geometry form the very beginning. It seems > > that even among mathematicians there is a difference of opinion on the > > following fundamental issues: (1) Whether a point occupoies space or > > does not occupy space. > [snip]
> You have made your point that you know nothing. Rather than continue > eructating amidst thinking people who loathe you, why don't you infest
^^^^^^^^^^
Thanks again for the vocabulary building.
> religious newsgroups and delite your peer group of loud morons spewing > revelation and inerrancy?
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In article <38af3945.0211030641.722c8...@posting.google.com>,
vgopa...@rediffmail.com (V.Gopal) wrote: > It seems that the cunning policy: "It is better to be vague and partly > correct than to be precise and completely wrong" is applied > particularly to coordinate geometry form the very beginning.
What is there about co-ordinate geometry that annoys you so? Did you fail a class in it or something? Your crusade against it seems completely unreasonable, but you must have your reasons.
> It seems > that even among mathematicians there is a difference of opinion on the > following fundamental issues:
Seems to whom? Please cite a *single* bona-fide mathematician (not some Usenet crank) who has the slightest problem with the foundations of co-ordinate geometry.
(1) Whether a point occupoies space or does not occupy space.
This actually can be a meaningful question in point-set topology. As applied to Euclidean space, a point does NOT occupy space. Do you have a cite of some mathematician who claims that it does?!?
> (2) Does a point specify only 'location' and not a number?
Huh? In co-ordinate geometry, a location IS a tuple of numbers. Do you have an example of the distinction between the two that you are trying to get at?
> (3) Whether each point has to represent the same number > OR a point can represent any number from 0 to infinity,
Since each point IS a tuple of numbers, why ask whether it can be several different tuples? Clearly it can not.
> e.g. any value of TanA.
What *is* there about tan(A) that intrigues you so? Is it the fact that tan(pi/2) is infinite? If so, this would also explain your fascination with the hyperbola XY=1.
> (4) Whether a line becomes contiguous/continuous if we > ADD points to a line one AFTER another (assign value of X, then > calculate the value of Y and finally place the point on its > appropriate position) or it requires a different condition.
There is no disagreement among mathematicians about this; it does require "a different condition" in the general case. Clearly, a line with a countable number of point holes in it can be filled in by the procedure you describe. But, as Cantor showed, the number of points in a line segment (such as a gap in your discontinuous line) is vastly greater than the number that can be filled in one-at-a-time.
HTH, really.
-- --------------------------- | BBB b \ barbara minus knox at iname stop com | B B aa rrr b | | BBB a a r bbb | | B B a a r b b | | BBB aa a r bbb | -----------------------------
> "space" is not math it's physics, in ph there is no point -> everything > occupies space
> > (2) Does a point specify only 'location' and > > not a number?
> a one dimensional point is a number
> > (3) Whether each point has to represent the same number > > OR a point can represent any number from 0 to infinity, e.g. any > > value of TanA.
> I didn't really get the question. but two equal points represent the > same number ...
> after all everything's a matter of definition
> akalos
In fact, in physics the word used for mass is 'point mass' or 'mass point'. The path along which it moves is a 'line'. "A consistent field theory requires continuity of all elements of theory, not only in time but also in space, and in all points in space. Hence neither the concept of point mass nor that of motion can play a part in a field theory." I am not talking of Field physics. I am talking of coordinate geometry. In geometry can we use a point to represent 0, one point to represet 10^-100, then one point each to represent 10^-10, 1, 10 etc? In this context I am asking whether a point has to represent the same number? Do you mean that points have size when you use the phrase "equal points"? I believe that each line has to represent one and the same number and to represent another number we have to use another line and these lines cannot intersect each other. If 0 to 1 is continuous then we must have infinite number of parallel lines to cover all the numbers between 0 and 1. For those who bring in religion into geometry - I cannot understand in waht way religion is connected to geometry. In any case I do not believe that God can perform miracles.
Is a mathematical point a physical point or, to make my point, a philosphical point?
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> Is a mathematical point a physical point > or, to make my point, a philosphical point?
Yes, but physical points aren't mathematical points, since Einstein wannabees need to be reminded to use 12pt type in their writeups or they'll be mistaken for Heil Hilter wankers once again, and have to be Schroedinger's non-existent cat nuked again. Or even continously erased by the nonexistent continuum.
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"William Elliot" <m...@xx.com> wrote in message > A point is a point is a point.
If you can't explain something simply, you don't know enough about it. -- Albert Einstein
> Is a mathematical point a physical point > or, to make my point, a philosophical point?
_ Yes, but physical points aren't mathematical points,
As far as the laws of mathematics refer to reality, they are not certain, and as far as they are certain, they do not refer to reality. -- Albert Einstein; www.phnet.fi/public/mamaa1/einstein.htm
_ since Einstein wannabees need to be reminded _ to use 12pt type in their writeups or they'll _ be mistaken for Heil Hilter wankers once _ again, and have to be Schroedinger's non-existent _ cat nuked again. Or even continously erased by _ the nonexistent continuum.
Are you appealing, to some invocation That is revealing, a small revocation For my repealing, your incantation?
Pointfullessness Now changing the point, to make my point which is the point I deserve for pointing out the most pointedly pointed point ever pointed, may I point out to you, the point I wish you to appoint me without disappointment at our next appointment? -- the archives of Will's Will
----
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> jim.hun...@jhuapl.edu > "William Elliot" <m...@xx.com> wrote in message > > A point is a point is a point.
> If you can't explain something simply, you don't know enough about it. > -- Albert Einstein
> > Is a mathematical point a physical point > > or, to make my point, a philosophical point? > _ Yes, but physical points aren't mathematical points,
> As far as the laws of mathematics refer to reality, they are not > certain, and as far as they are certain, they do not refer to reality. > -- Albert Einstein; www.phnet.fi/public/mamaa1/einstein.htm
As far as gravity refers to anything except self-reflecting morons, we'll assume that Einstone wasn't a complete dork, but merely a partial dork.
God only plays with dice, he does not play with real number reality wankers, since reality is too complex for idiots like tensor goobs to even partially understand
On Mon, 4 Nov 2002, James Hunter wrote: > "William Elliot" <m...@xx.com> wrote in message > > jim.hun...@jhuapl.edu > > "William Elliot" <m...@xx.com> wrote in message > > > A point is a point is a point.
> > If you can't explain something simply, you don't know enough about it. > > -- Albert Einstein
> > > Is a mathematical point a physical point > > > or, to make my point, a philosophical point? > > _ Yes, but physical points aren't mathematical points,
> > As far as the laws of mathematics refer to reality, they are not > > certain, and as far as they are certain, they do not refer to reality. > > -- Albert Einstein; www.phnet.fi/public/mamaa1/einstein.htm
> As far as gravity refers to anything except self-reflecting > morons, we'll assume that Einstone wasn't a complete dork, > but merely a partial dork.
Yaba Daba Doo! Are you Flintstone?
> God only plays with dice, he does not play with > real number reality wankers, since reality is too > complex for idiots like tensor goobs to > even partially understand
Tensor goobs? Some candy your mother gives you?
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> On Mon, 4 Nov 2002, James Hunter wrote: > > "William Elliot" <m...@xx.com> wrote in message > > > > As far as the laws of mathematics refer to reality, they are not > > > certain, and as far as they are certain, they do not refer to reality. > > > -- Albert Einstein; www.phnet.fi/public/mamaa1/einstein.htm
> > As far as gravity refers to anything except self-reflecting > > morons, we'll assume that Einstone wasn't a complete dork, > > but merely a partial dork.
> Yaba Daba Doo! Are you Flintstone?
> > God only plays with dice, he does not play with > > real number reality wankers, since reality is too > > complex for idiots like tensor goobs to > > even partially understand
> Tensor goobs? Some candy your mother gives you?
Moma always said that Tensors are the bubble gum of logic dude, since it's only rolling, bent-dick, religoid mathemawankers and their Jesuit stand-ins who believe in moron SPACE-TIME to begin with.
vgopa...@rediffmail.com (V.Gopal) wrote in message <news:38af3945.0211030641.722c8a39@posting.google.com>... > It seems that the cunning policy: "It is better to be vague and partly > correct than to be precise and completely wrong" is applied > particularly to coordinate geometry form the very beginning. It seems > that even among mathematicians there is a difference of opinion on the > following fundamental issues: (1) Whether a point occupoies space or > does not occupy space. (2) Does a point specify only 'location' and > not a number? (3) Whether each point has to represent the same number > OR a point can represent any number from 0 to infinity, e.g. any > value of TanA. (4) Whether a line becomes contiguous/continuous if we > ADD points to a line one AFTER another (assign value of X, then > calculate the value of Y and finally place the point on its > appropriate position) or it requires a different condition.
Hi, where did you learn mathematics? It seems there must be something non-standard about your education, for the confusions I find in your postings are not the ones I am used to finding. Below you will find geometry the way I like it most. Hopefully it will answer some of your questions, and hopefully you and others will enjoy reading it.
Consider an n-dimensional Euclidean space S. In it we have (Euclidean) subspaces of dimensions less than n. I will use the following synonyms: A point is a 0-space. A line is a 1-space. A plane is a 2-space. I will assume in what follows that n > 2, so that I can illustrate some things I want to illustrate.
We have S, and we know there are points, lines, planes, m-spaces (0 <= m < n) on it, but we do not have any of theese points, lines or planes; we cannot *point to* any point, line, or plane.
Suppose now that someone gives us a point P of S. We can now point to P, and not only that: the fact that we are given P means that the other points divide themselves according to how far away from P they are. For along with a point we automatically have the (n-dimensional) spheres centered at the point (though we cannot as yet point to any particular (n-)sphere). In addition, lines, planes, and more generally m-spaces, can be divided into those passing through P and those not passing through P.
Let us go on and suppose that someone gives us another point Q. Among the spheres we got when we got P, we can now distinguish the one on which Q is located. Let us use s_AB to denote the sphere centered at A that passes through B. Then we now have s_PQ. Also, among the lines passing through P we now note the one that also passes through Q. By line AB I will understand the line passing through points A and B; so what we now have is the line PQ. We can also look at things from the point of view of Q. Forgetting about P for a second, we then have the (n-)spheres with center at Q, and for any m (> 0, < n) m-spaces are divided into those that pass through Q and those that do not. With P we then have the sphere at Q on which P lies, that is, s_QP. For any m-space M we now have four possibilities: ~(P on M) & ~(Q on M) ~(P on M) & (Q on M) (P on M) & ~(Q on M) (P on M) & (Q on M) ("~" stands for "not," "&" stands for "and," and "M on N" means that space M is part of space N. In particular, if dim(M)=1, and dim(N)=2, then "M on N" means point M lies on line N.) Actually, more can be defined. For example, there is the unique point that lies precisely between P and Q, and there is a unique (n-1)-space having the property that points on it are just as distant from P as from Q.
We could go on this way and ask what we can point to when various things are given to us (I recommend it as an exercise), but I will now turn to something else. With all theese geometrical objects one can ask the question: do they exist? My personal opinion is that geometry should be understood in a way that makes this a meaningless question, but normally another approach is taken, and as part of axiomatisations of geometry one consequently has to state things like "there exists n+1 points such that no (n-1)-space contains them all." With the approach I prefer one speaks (or can speak, anyway) about *being given* things, and also, no importance is put on the particular way one describes what one has. An example of the latter is that I do not have to speak about points and lines at all; any way of representing what I have is fine.
More interestingly, we can speak about so-called points at infinity. A point at infinity is where parallell (that is, non-intersecting) lines intersect each other. For any collection of parallell lines there is exactly one point at infinity through which they all pass. Thus, given any two lines they intersect at exactly one point, either a normal one or one at infinity. I hope you get the idea. More generally, it is useful to consider m-spaces at infinity. For example, given two points at infinity there is a unique line passing through both, and this line is a line at infinity. Another example is that given two points at infinity and one normal point there is a unique plane passing through all three.
Through the approach I prefer, we can completely avoid questions like whether points at infinity exist. The one who asks whether they exist has introduced a new concept (that of existence) and the question cannot be answered until the questioner specifies what she understands by that concept. Not only do we avoid the question as to whether points at infinity exist, we also avoid having to choose between various continuity properties. An example of a continuity property (one called the circular continuity principle) is "given two circles c1 and c2 in a plane p that have points inside each other, c1 and c2 intersect at exactly two points." With the normal meaning of point this is true, but with a non-standard meaning it could be false. The important thing here is that given points in one sence we can introduce points in another sence. Henceforth points will be understood to have the same completeness proprty as the real numbers. This can be stated thus: any Cauchy-sequence of points converges to a point (if you do not know what this means it does not matter).
Points are distinguished from spaces of dimension > 0 in that they "have no parts," but this does not mean we cannot introduce parts if we like. Consider a line l with the two directions D1 and D2 (I hope the meaning of a direction is intuitively clear), and consider a P of l. We can think of P as a combination of "P from the direction D1" and "P from the direction D2." We could also speak about things like "approaching P at speed s" or "approaching P at speed s from the direction D." The important thing is that having parts, like existance, is a bit relative. For example, a line can be thought of as the collection of all points on it, but it is equally possible to think of a point as all the lines passing through it. That said, there is an obvious sence in which a point has no parts and in which spaces of dimension > 0 have parts. By now, everyone reading this posting must have noted that I am not particularly "formal". Actually, my philosophy is that it does not matter at all how we choose to convey an idea. We can use diagrams, formal notation, informal English, or anything we like.
Let S be a space. Let Congr(A, B, C, D) stand for "line segment AB is congruent to line segment CD." In a sence, this relation is all there is to geometry, for out of it everything else can be defined (it is not the only relation having this property, though). Note that Congr is given as soon as the space is. Congr is not particularly convenient to use. It would be more practical to have a function dist(A, B) which given points A and B gives us their distance. One could then define Congr as Congr(A, B, C, D) <-> dist(A,B) = dist(C, D), and one could write easy-to-read things like 4 * dist(A, B) = 3 * dist(C, D). It would be easy to say what properties distances must satisfy, and obviously theese properties would be satisfied by real numbers. The problem is that out of what we are given we cannot define a function that given two points gives us a real number. Distances and angles are different in this respect. So what are we to do? We may inelegantly assume that two points determining a unit of length are given (this is inelegant because the points must be arbitrarily chosen), but let us opt for the elegant approach. This means we must think of distances as something other than numbers. We could call them quantities. For the moment I will assume we understand intuitively what distances are.
Now that we have distances, the only think we lack is the concept of direction. It is intuitively clear what a direction is, so I need not say much about it. For any direction D there is an opposite direction -D, and {D, -D} (the class consisting of D and -D) corresponds directly to a point at infinity. Directions will enter the geometry when we consider motions in a given direction, which is what we will now do.
For each combination of a direction D and a distance d there corresponds what I will call an adder a = add_D_d, which given a point P gives us the point a(P) that lies in the direction D relative to P and lies at distance d from P. What I have named adders we could name motions, but the name adder makes sence when what I call multipliers are also considered. A multiplier could also be called a magnifier. It takes an adder and magnifies or shrinks it. For example, there is an identity multiplier m_id that leaves the adder it gets unchanged, and there is a doubler that given an adder a1 gives us an adder a2 such that a2(P) = a1(a1(P)) Here it is appropriate to make some definitions: a1 + a2 = a1a2 = the adder which for any point P gives a1(a2(P)) m1 * m2 = m1m2 = the multiplier which for any adder a gives m1(m2(a)) m1 + m2 = the multiplier which for any adder a gives m1(a)m2(a) (m)(d) = the distance which is "m times as great as" d Note that multipliers
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