Is Zero a Whole Number?

But to define 'one', don't you need multiplication? Hence a ring rather than just a group...
 
Pete said:
In that vein, would it be sufficient to define the integers as those number that can be obtained by adding and subtracting ones?

Or more formally, how about "the intersection of all additive groups that include one."

Pete (not a mathemetician)

Z is called an infinite cyclic group. The informal definition of this is a group (a set and an operation as defined by a previous post by me) that can be defined by the products of one element in the group. These products are g<sup>0</sup>, g<sup>1</sup>, g<sup>2</sup>, ... and g<sup>-1</sup>, g<sup>-2</sup>, g<sup>-3</sup>, ... Product just refers to the opperation. In this case, addition. So, g<sup>-2</sup>, = g<sup>-1</sup>g<sup>-1</sup>, (-1) + (-1) = -2. The element in g is 1.

I think I did a bad job of explaing that. Just look for it in wiki or mathworld.
 
Zephyr said:
But to define 'one', don't you need multiplication? Hence a ring rather than just a group...

As far as I know... one and zero "just are." It's an assumption that 0 != 1. But nothing is said about 2, -2, 2.435... ect.

However, a neat proof I did one time was prove that 1+1 != 0 or 1. Since that is the case.. what do you do? You make up a number. In this case, we call it "2." Then you do the same thing for the next numbers.

Show 1 + 2 != 0, 1, 2. So call it 3.
Show 1 + 3 != 0, 1, 2, 3. So call it 4.

Then you just show a general rule for defining new numbers.

It seems like a coward way to go.. .define a new number. However, don't you remember imaginary numbers? Sqrt(-1). WTF? Well, let's just call it i.
 
Absane said:
As far as I know... one and zero "just are."
Well, one 'is' in rings with unity ... 2Z with the usual operators, on the other hand, has no multiplicative unit :p

And I think giving names to stuff you don't understand is a better approach than ignoring them ... wasn't there a group of Greeks who insisted there could be no irrational numbers? That must have put a bit of a dent in their research ability...

"Hey Obstinopolis, you've spent five years looking for the fractional form of the squareroot of two. Don't you think you should take a break?"
"You're right, Tumuchondaplato ... I'll start on the squareroot of three tomorrow."
 
I think it's quite alright to look at x<sup>2</sup> - 2 = 0 and think... wow. What is x? Well, it seems I can get closer and closer to a number but cannot quite find it. Why not just call whatever this number is Sqrt(2)? There. Problem solved.

It's funny but hey.. what else can you do? WHen you work with faulty assumptions, you don't get anywhere. Assuming sqrt(2) is a fraction of two integers leads to a contradition.
 
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Absane said:
It's an assumption that 0!= 1.
No. 0!=1 follows from extending the recursive form of the definition of factorials downward. It's not exactly an assumption, but more properly a convention.

(n+1)! = n!*(n+1), therefore

(n-1)! = n!/n

There is no definition for negative numbers because of the division by zero problem. I suppose by this same convention (-1)! = infinity.

As for non-integers... Has anyone tried to find a function that provides the right solutions for integers, which could then be interpolated for fractions?
 
Fraggle Rocker said:
No. 0!=1 follows from extending the recursive form of the definition of factorials downward. It's not exactly an assumption, but more properly a convention.

No what I meant was != means "not equal to." Sorry... it's just that != means that in programming.

Maybe I could have used <> or something.
 
Fraggle Rocker said:
There is no definition for negative numbers because of the division by zero problem. I suppose by this same convention (-1)! = infinity.

As for non-integers... Has anyone tried to find a function that provides the right solutions for integers, which could then be interpolated for fractions?

For negative numbers.. there is a definition for cominations and such. Like:

C(-4,2) = (-4)*(-4 - 1)/2!.

And for non-interegers.. the same thing applies. I got a formal definition somewhere but I don't think I really need to dig it up. It's used for things like Newton's Binomial Theorem.
 
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Fraggle Rocker said:
As for non-integers... Has anyone tried to find a function that provides the right solutions for integers, which could then be interpolated for fractions?

look up the "gamma function".



ps. it's a given that whenever someone writes "0!=1" it will be misinterpreted by someone to mean the thing it wasn't meant it to mean.
 
shmoe said:
ps. it's a given that whenever someone writes "0!=1" it will be misinterpreted by someone to mean the thing it wasn't meant it to mean.
Heh. Moral of the story: don't mix maths and C.

If Sciforums supported LaTeX, wouldn't it be easier to add in characters like '≠'? (Instead of having to dredge up character-map)
 
I realize that we have been taught all of our lives that zero isn't a number, rather it's a placeholder.

I have never met anybody who would agree with this.


Counting is a logical process of repeating a cycle of increments contigent upon the base. Zero is either the beginning or end of a base cycle. When the base count is achieved, then the cycle resets to zero and repeats itself.

Counting is not a process of repeating a cycle of increments contigent upon the base. Only for convenience do we use a base to count. What about match stick counting, i.e. 1, 11, 111, 1111, 11111...? How is this repeating a cycle of increments dependent upon a base? How would your idea work if you were counting in Roman numerals? And even in base counting the cycle doesn't reset to zero, otherwise we'd be trapped counting in modular arithmetic where 10=0 (in base 10).
 
stanleyg said:
EXAMPLE

2 + 2 = 4 or 2 - 2 = 0 or 2 X 2 = 4 or 2 / 2 = 0

The problem is assigned to the left side of the equation and the solution is assigned to the right side of the equation. Each side balances with each other.

The solution to any problem is to create a balance.

Zero = balance
One = imbalance

Whenever we have problems then it means that a one is hidden in the equation creating an imbalance. Eliminate the one and the problem is solved.


Two divided by Two does not equal Zero. It equals One
 
DJ Erock said:
Two divided by Two does not equal Zero. It equals One

Do you see what he was doing? He made a faulty analogy.

2 + 2 = 4 : 2 - 2 = 0 :: 2 X 2 = 4 : 2 / 2 = 0.

Division is defined in terms of addition and multiplication. Subtraction is defined in terms of addition. He assumes that multiplication is repeated addition (in some ways, it is.. but not in general). He also assumes that division is repeated subtraction (in some ways, yes.. but not in general). Again, division is defined in terms of multiplication and addition, not subtraction.
 
Much of this thread is nonsense which seems to have been pointed out as such by others.

As far as I know, mathematicians do not view zero as having a sign, although there are functions which approach zero from below. I have never heard of any claim that the limit of such a function is different from the limit of a function which approaches zero from above.

The only context in which I have encoutered negative zero is in the arithmetic units of (circa 1957-1963) computers, using signed magnitude values. For at least one such computer, the machine language branch (Goto) if zero command did not branch (go) for negative zero. This caused a bit of extra work for competent programmers.

Due to an incompetent programming staff at some department stores, an inactive account could be dunned for a negative zero balance. Almost any activity would get rid of the anomaly. It occurred if you had a credit balance of $X and charged an item costing exactly $X.

Several of us amused ourselves by deliberately causing a negative zero balance and collecting the dunninbg letters, climaxed by one threatening legal action for failure to pay the zero balance, which appeared on statements as zero without a sign.
 
Dinosaur said:
climaxed by one threatening legal action for failure to pay the zero balance, which appeared on statements as zero without a sign.
I rmember an anecdote that circled via email - someone got a statement like that, so he sent them a cheque for $0 and got a reply saying his cheque had crashed the system.

The last part may be fictional though :p
 
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