Infinite number of elements in some sets but no infinitely large number

JeffM,

I believe that subscripts should be defined before they are use, at least in non-axiomatic systems. I haven't been able to make subscripts render correctly on this site, so I have a link to the section on subscripts here:



Jim Adrian
 
JeffM,

I worry when properties are listed before a definition is stated or instead of a definition. I comment after the definition of equals:

Definition - A is equal to B or A equals B if and only if either of the following statements is true:

A describes or names a quantity, and B describes or names the same quantity.

A describes or names a set of quantities, and B describes or names the same set of quantities.
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Notice that is A equal B, then B equals A. This is true because they both describe or name the same thing. By repeatedly applying the definition, it follows that if A = B and B = C and C = D that A = C. A is equal to B or A equals B may be written A = B or B = A. Of course set is previously defined.

I don't see how to achieve a formal definition of equals by listing such properties alone, but it might be different for the natural numbers. I suspect that the natural numbers are sufficiently engrained in the minds of mathematicians that it is taken as an agreed feature of reality. Is that right? This was the view of my math teachers in college. I don't know if that is exactly your view.


Jim Adrian
 
Defining numbers and sets and methods of calculation without axioms is merely another way to get math. It is not meant to offend anybody.

It seems to be more accepted as an alternative by mechanical engineers and software engineers than by mathematicians.

I am posting definitions because I hope to get feedback about their clarity. I also appreciate suggestions about which conclusions or results should be sought before others or most importantly.

It might get more interesting to mathematicians later in its development. There are some open questions.

Gödel's 1931 incompleteness theorems of mathematical logic demonstrate that in every formal axiomatic system capable of modeling basic arithmetic contains true statements that cannot be proved.

I suspect that a system of definitions would be incapable of proving Gödel's theorems.

I don't yet know if there could be useful orders of unbounded sets in a system of definitions.

Would there be any other valued results that might not be obtained by a system of definitions?


Jim Adrian
 
Dan,

You are absolutely right that the definition is not true if P is not finite.

I have not yet defined the operation of addition. I have thrown out this definition.

Here is a new one for your consideration:

Definition - M is the successor of N if and only if the following statements are true:

P is a set of elements.

K is a set containing one element.

The intersection of K and P is empty.

N is the number is element in P.

R is the union of P and K.

M is the number of elements in R.
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Jim Adrian

Dan,

This definition is defective. I'm trying to do this too fast.


Jim Adrian
 
There are several terms in the common language that are associated with the concept of order. Here, I mention those that are not capable of being scientifically defined. Attempts to do so invariably exhibit circularity. The descriptions made in the attempted definitions employ synonyms. This makes the descriptions circular. There is a simple reason for this: These meanings are too basic to be described by more basic terms.

The concept of order is inherent in matters of time, distance, rank, and other common terms. One need not mention the term order when using terms such as before, after, left, right, next in line or next in time. The order of time is thoroughly conspicuous.

The term next can mean that something is juxtaposed to something, or it can have the meaning associated with order in which it means next in order. This is the sense of the term that will be used here, unless explicitly stated otherwise.

Like these terms that are associated with order, the term order itself is not capable of being scientifically defined. It is learned through experience in the world.

To say that the applause event is next in order to the curtain falling event is unambiguous.

Please keep in mind that elements can be events, actions, statements, or things of any kind. Also, lacking an axiom of infinity, you can call sets here finite.

Definition - S is an ordered set if and only if the following statements are true:

S is a set containing at least a pair of elements (at least two elements).

A single element j in S is the only element in S that is not next in order to some other element in S.

A single element k in S is the only element in S such that there is no element in S which is next in order to k in S.

If element y is next in order to element x in S, then no element other than y is next in order to x in S.
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Notation - In the case of an ordered set, the curly brackets that are normally used to enclose elements in a set are replaced by parentheses. Unless otherwise specifically required, if y is next in order to x, then y is written to the right of x. Here is an example:

S = (t, u, v, w, x, y, z)

In 1921, Kazimierz Kuratowski offered the now-conventional definition of the ordered pair (a, b):

(a, b) = {{a}, {a, b}}

This equation cannot be used in the system of definitions because the axioms of traditional set theory that give this equation meaning are missing.


Jim Adrian
 
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I have defined the integers and much more, so suspicions that math could not be created with a system of definitions lacking axioms should no longer be believed.

I wonder if the objection to a system of definitions might be because it is not the least bit abstract. I think that abstractness can be valued, more by mathematicians than by programmers and engineers.

This system uses rational numbers and processes that produce rational numbers. That is the reason for the title.

I would be curious about your opinions about this.

To me, it is just another way to facilitate calculating for programmers and engineers.



Jim Adrian
 
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