The random function's universality of multiplicative identity

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The discussion centers around the concept of the multiplicative identity of a random function r(x) and its interaction with a non-random mapping f(x). It asserts that multiplying r(x) by any non-zero function f(x) retains the randomness of r(x), except when f(x) equals zero. Participants explore the implications of this relationship, questioning whether it can be used to find zeros of f(x) and how the definition of randomness might need to be refined. Concerns are raised about maintaining the properties of r(x) when multiplied by f(x), particularly regarding the range of values produced. The conversation also touches on the nature of random functions, their probability distributions, and the potential for modular arithmetic to maintain randomness within finite bounds. Overall, the thread delves into the complexities of defining and manipulating random functions in mathematical contexts.
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The multiplicative identity of the random function r(x) is any other function f(x) except where f(x)=0.
 
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In other words, a field in x of random values r(x) each multiplied by a corresponding value for a (non-)random mapping f(x), always retains a random mapping r(x), except where f(x)=0.

Can you imagine this situation?

Also, may this be a great way (in theory) to obtain 0's of f(x)?
 
What if f(x)=k/r(x) ? Huh ?
Maybe you wanted to say f(r(x))...or I just don't understand...:frown:
 
Originally posted by Loren Booda
In other words, a field in x of random values r(x) each multiplied by a corresponding value for a (non-)random mapping f(x), always retains a random mapping r(x), except where f(x)=0.

Can you imagine this situation?

Also, may this be a great way (in theory) to obtain 0's of f(x)?


Does it always maintain the properties of the random function r(x). For example you might have specified that if the domain is the real numbers, the function r(x) returns values in the interval [0, 1], multiplying this by 2 does not preserve this property.

Do you need to make your definition of randomness more tight, or am I missing something.

As to Bogdan's point, f(x)=k/r(x) will be a random function...and thus not allowed by the Loren Booda's initial statement.
 
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In a set X equipped with a binary operation called a product, the multiplicative identity is an element e such that e * x = x * e = x, for all x in X...got it...

So e = f(x)...hmmm... r(x)*f(x)=r(x)...hmmm...still don't get it...
 
Originally posted by bogdan
What if f(x)=k/r(x) ? Huh ?
Maybe you wanted to say f(r(x))...or I just don't understand...:frown:

Certainly he does not mean f(r(x)) as you could just set f(x) = 1 for all x.

What he appears to be saying that there if r contains no information, i.e. it returns a value on the range with equal probability, then multiplying it by any conventional (not including random) and not equal to zero at x ,function returns a result which contains no information as defined above.

Perhaps his statement is more general?
 
I don't know for sure...maybe he'll explain better...
 
plus
Does it always maintain the properties of the random function r(x). For example you
might have specified that if the domain is the real numbers, the function r(x)
returns values in the interval [0, 1], multiplying this by 2 does not preserve this
property.

Do you need to make your definition of randomness more tight, or am I missing
something.
What is returned is the property of randomness, apparently not the function itself as first defined. Indeed I need to "loosen" my definition of random r(x). Perhaps I should require its returned interval to be [-[oo],[oo]]. Thanks for your feedback.

I hope this helps your understanding of the problem also, bogdan?
 
Yeap...if (non-)random means not random... ...those brackets...
 
  • #10
bogdan-

A random number times a random number, or times a non-random number, is a random number.
 
  • #11
But why ?
if f(x)=1/r(x), then both are random...
Or am I just stupid ? Or worse ?
 
  • #12
What is the probability distribution of your random function on the real line going to look like?
 
  • #13
Actually, plus, I don't know if r(x) can be "seen," as its average magnitude may be infinite. Can you think of a finite random function that returns the property of randomness to similar bounds (or better yet, as I initiated, the random function itself?) Perhaps I should require normalization of r(x) and r(x)f(x)?

bogdan, I appreciate your interest too. Think of a random function with magnitude r(x) returning values from 0 to [oo], multiply each by a nonzero arbitrary number f(x), and one returns the random function along x. The cardinality of "randomness" apparently is greater than that of the real number line.
 
  • #14
The only way I could think of to get this in a finite range would be to have modular multiplication. so if it was mod 10,

8.18* 10 = 0.9 (mod 10)
 
  • #15
Beautiful idea. The credit is yours. Do your see any application for the infinite range r(x) (like finding zeroes of a function)?
 
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