Symbolica question: Is "F(X) = A(d)Δ -> C(d)Δ" correct?

L

line7

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Hello!

I need to correctly represent the following relationship = daily change in A tends to follow the daily change in C. The higher the C the higher will be the A and vice versa. I write this formula:

F(X)=A(d)Δ->C(d)Δ


Not sure if this correct - can you help me to present this relationship symbolically?

Dave
 
line7 said:
Hello!

I need to correctly represent the following relationship = daily change in A tends to follow the daily change in C. The higher the C the higher will be the A and vice versa. I write this formula:

F(X)=A(d)Δ->C(d)Δ

Not sure if this correct - can you help me to present this relationship symbolically?
Click to expand...

Your notation can't be correct, because delta is always written before something.

Can you explain a little more? Does "tends to follow" mean "is proportional to", or something more vague? And is there a reason you wrote A and C as what I take to be functions of some d? And what does F(X) represent? The more you explain, the more likely we can figure out what you need.

It's also possible that there is no notation for what you want to say, and you just need words. Is there a reason to use symbols?

Also, you first said the changes are related, but then said that the actual values "follow" one another. Which is it, really?
 
Dr.Peterson said:
Your notation can't be correct, because delta is always written before something.

Can you explain a little more? Does "tends to follow" mean "is proportional to", or something more vague? And is there a reason you wrote A and C as what I take to be functions of some d? And what does F(X) represent? The more you explain, the more likely we can figure out what you need.

It's also possible that there is no notation for what you want to say, and you just need words. Is there a reason to use symbols?

Also, you first said the changes are related, but then said that the actual values "follow" one another. Which is it, really?
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Thank you for your detailed reply.... I absolutely need to formualte this relations in symbols as htis is a very important relationship....By this relatioship I mean if C falls sharply A will also fall sharpy....if C fals slowsly - A
will likely fall slowly as well...cannot the limit sign be used? → I need to formulate that the degree of daily change in A is directly proportinal to the daily degree of change in C and C is the LEADING FACTOR....can you help me with this?
 
line7 said:
Thank you for your detailed reply.... I absolutely need to formulate this relation in symbols as this is a very important relationship....By this relationship I mean if C falls sharply A will also fall sharpy....if C falls slowly - A
will likely fall slowly as well...cannot the limit sign be used? → I need to formulate that the degree of daily change in A is directly proportional to the daily degree of change in C and C is the LEADING FACTOR....can you help me with this?
Click to expand...

line7 said:
f(x) means this is a function or it should include the X sign?
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It is very different to say that two quantities are "likely" to vary in the same direction, and to say that they are in fact directly proportional. Your idea of using a limit (is that what you mean by the arrow?) suggests that in fact it is not a definite relationship, but, as you initially said, a tendency, and not necessarily an actual proportion (which means not only that if one increases rapidly, the other will increase rapidly, but specifically that if one doubles, the other exactly doubles). But what you describe has nothing at all to do with limits; at most, it would be about approximate relationships. We use the word "tends" in talking about limits, but not in the same sense you are using.

Again, you are ambiguous about whether it is the value of A that follows that of C, or the change in A following change in C. There can be very different.

If you really mean that A is directly proportional to C, then there is a symbol (\(\displaystyle A\propto C\)) that means that; or if it is only approximate, you could say \(\displaystyle A\approx kC\), or perhaps \(\displaystyle \Delta A\approx k \Delta C\).

There is no need to name a function, especially a function of a variable, X, that you have not defined. If anything, you would be saying that A is a function of C, \(\displaystyle A = f(C)\); but that tells us nothing about what particular relationship the function represents, so it is not helpful.

Can you tell us the actual context of your question? We can answer much better if we know what these quantities are, and what relationship they really have.
 
Thank oyu for your detailed reply.....Can it be rephrased like this:

Difference between A and C tends to ZERO with C rising?
 
lET SAY THERE IS THIS RELATIONSHIP

P TENDS TO BE EQUAL TO S WITH ABSOLUTE VALUE OF S RISING TO 1

CAN YOU HELP ME FORMUALTE THIS IN SYMBOLS?

IF ABS(S) IS LOW THEN P WILL NOT BE EUQAL TO S BUT WITH ABS(S) RISING P WILL TEND TO BE EQUAL TO S

THIS IS A VERY BASIC RELATIONSHP BTU IT DESCRIBES MOST OF WHAT THE MARKETS DO INTRADAY
 
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line7 said:
lET SAY THERE IS THIS RELATIONSHIP

P TENDS TO BE EQUAL TO S WITH ABSOLUTE VALUE OF S RISING TO 1

CAN YOU HELP ME FORMUALTE THIS IN SYMBOLS?

IF ABS(S) IS LOW THEN P WILL NOT BE EUQAL TO S BUT WITH ABS(S) RISING P WILL TEND TO BE EQUAL TO S

THIS IS A VERY BASIC RELATIONSHP BTU IT DESCRIBES MOST OF WHAT THE MARKETS DO INTRADAY
Click to expand...

Did you lose your caps lock key?

Perhaps you should have submitted this on the Finance forum; those people might have a better idea what you are talking about. Until now, you haven't given any indication of the context of your question, which might have helped people understand you.

I am not at all sure what you mean by "P tends to be equal to S with absolute value of S rising to 1". Without knowing what you mean, there is no way to put it into symbols.

Possibly you mean something like this: S is a number between -1 and 1. As |S| increases (toward 1), P approaches S. That would be a limit issue: the closer |S| is to 1, the closer P is to S (always).

But I don't think that your use of "tends" is the same as what we mean in talking about limits. I think you are referring more to probability: if S is close to 1, then P will probably be close to S, but is not guaranteed to be equal to S, or even necessarily close. If so, then some sort of probability statement would make more sense.
 
yes sorry about the caps)

this is rather a probability that P will equate S (I guess it can be expressed as limit?) which tends to rise to 1 with abs(s) approaching 1
finance forius cannot help me formulate this mathematical relatiohsip properly - can you help???

the probability rises to 100% with abs(s) approching 1
 
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line7 said:
now that you moved the thread fewer mathmeticians will be able to help me((((

Dr.Peterson where are you?)
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The move was at my suggestion. We can all see all the forums. This forum is not for non-mathematicians; putting it here just alerts those of us (not including me) who have special knowledge of financial math. That may be necessary in order to understand what you are trying to express, which is not something that pure mathematicians do.
 
Dr.Peterson said:
The move was at my suggestion. We can all see all the forums. This forum is not for non-mathematicians; putting it here just alerts those of us (not including me) who have special knowledge of financial math. That may be necessary in order to understand what you are trying to express, which is not something that pure mathematicians do.
Click to expand...

thnak you but do you think you can help me formualte this relationship?
 
This is a very quick preliminary response. I am traveling and cannot devote much time to a dialogue until late Tuesday.

The language of modern economics and finance is very mathematical, and I may not be able to help you to a conclusion, either because I do not know the math involved or am not familiar with the specific economic literature involved. But the very first thing to do is to get the vocabulary straight so we can determine what body of economic literature may be relevant and what branch of mathematics may be involved.

Before I try to formulate any relationship in abstract mathematical terms, let's determine what we are even talking about concretely. At this point, I am fairly confident that you are talking about prices, but I have no idea how many different prices or what the absolute value function has to do with anything. And I have a suspicion that we are talking about probability functions or perhaps expected values.

Are we talking about a possible relationship between the prices of a single stock over time or between the prices of multiple stocks at the same time or something more complex such as the relationship between the prices of a stock and options on that stock over time?

Can you explain in English what you believe the relationship between or among the variables of interest is? For example, the price of a call option is likely to rise if the price of the optioned stock rises. Words like "limit" and "expected value" have very precise meanings in math so just try to explain what you mean in simple English first.
 
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