What does this notation "<>" mean?

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Discussion Overview

The discussion centers around the notation "<>" and its meaning across different contexts, particularly in mathematics and programming. Participants explore its usage in various disciplines, including quantum optics and calculus, and examine instances where the notation appears to be misused or incorrectly formatted.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants note that different disciplines have varying conventions for notation, with one mentioning its use in quantum optics to denote expectation values.
  • One participant provides a quotation from a webpage discussing the Intermediate Value Theorem, highlighting the appearance of "<>" and questioning its meaning.
  • Another participant suggests that the notation might be a typesetting error from the webpage, indicating that it could be intended as a mathematical inequality.
  • Several participants speculate that the "<>" notation may result from an auto-completion feature in the editor used to create the webpage.
  • Some participants mention that in certain programming languages, "<>" can signify "not equal to," adding another layer of context to the discussion.
  • There is a suggestion that the notation is likely gibberish in the context provided, as it does not convey a clear mathematical meaning.

Areas of Agreement / Disagreement

Participants express a range of views regarding the notation "<>", with some proposing it as a typesetting error while others suggest its meaning in programming contexts. There is no consensus on its intended use or significance in the mathematical examples provided.

Contextual Notes

Limitations include the unclear formatting of the quoted material, which may lead to misinterpretation of the notation. The discussion does not resolve the ambiguity surrounding the notation's meaning in the provided examples.

5P@N
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So: what does "<>" mean?
 
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Oh, my...what does "><" mean?
:confused:
 
Different disciplines have different conventions.
I work in quantum optics, and we use that notation \langle x \rangle to denote the expectation value (or mean) of the thing x inside the brackets.
 
5P@N said:
So: what does "<>" mean?

5P@N said:
Oh, my...what does "><" mean?
:confused:
Can you show an example of how these are used?
 
The following quotations are taken from the bottom of the page entitled "Continuity and Limits" From Wyzant <https://www.wyzant.com/resources/lessons/math/calculus/limits/continuity>...

"Intermediate Value Theorem
The Intermediate value theorem states that if we have a continuous function f(x) on the interval [a,b] with M being any number between f(a) and f(b), there exists a number c such that:

1) a < c=""><>

2) f(c) = M...
The Intermediate Value Theorem is a geometrical application illustrating that continuous functions will take on all values between f(a) and f(b). We can see if we draw a horizontal line from M, it will hit the graph at least once. If the function is not continuous on the interval, this theorem would not hold.

It is important to note that this theorem does not tell us the value of M, but only that it exists. For example, we can use this theorem to see if a function will have any x intercepts.

(1) Use the Intermediate Value theorem to determine if f(x) = 2x3 - 5x<> - 10x + 5 has a root somewhere in the interval [-1,2].

In other words, we are asking if f(x) = 0 in the interval [-1,2]. Using the theorem, we can say that we want to show that there is a number c where -1 < c="">< 2="" such="" that="" m="0" in="" between="" f(-1)="" and="">

We see that p(-1) = 8 and p(2) = -19. Therefore, 8 > 0 > -19, and at least one root exists for f(x)."

Note: I didn't bother with the grammatical tedium of putting the above quotations into proper nested quotes. But you can see the various "<>" and "><" quoted. What do these mean?

PS:
><
n
 
Looks like (typesetting?) errors on that webpage.
For example, this one:
5P@N said:
1) a < c=""><>
was meant to be 1) ##a<c<b##
 
5P@N said:
The following quotations are taken from the bottom of the page entitled "Continuity and Limits" From Wyzant <https://www.wyzant.com/resources/lessons/math/calculus/limits/continuity>...

"Intermediate Value Theorem
The Intermediate value theorem states that if we have a continuous function f(x) on the interval [a,b] with M being any number between f(a) and f(b), there exists a number c such that:

1) a < c=""><>
As far as I can tell, and looking at the web page you cited, it's meaningless. Most likely some weirdness in the web page. Same with the other ones you cited.
5P@N said:
2) f(c) = M...
The Intermediate Value Theorem is a geometrical application illustrating that continuous functions will take on all values between f(a) and f(b). We can see if we draw a horizontal line from M, it will hit the graph at least once. If the function is not continuous on the interval, this theorem would not hold.

It is important to note that this theorem does not tell us the value of M, but only that it exists. For example, we can use this theorem to see if a function will have any x intercepts.

(1) Use the Intermediate Value theorem to determine if f(x) = 2x3 - 5x<> - 10x + 5 has a root somewhere in the interval [-1,2].

In other words, we are asking if f(x) = 0 in the interval [-1,2]. Using the theorem, we can say that we want to show that there is a number c where -1 < c="">< 2="" such="" that="" m="0" in="" between="" f(-1)="" and="">

We see that p(-1) = 8 and p(2) = -19. Therefore, 8 > 0 > -19, and at least one root exists for f(x)."

Note: I didn't bother with the grammatical tedium of putting the above quotations into proper nested quotes. But you can see the various "<>" and "><" quoted. What do these mean?

PS:
><
n
 
My guess is the editor used to create the page had an auto completion feature meaning when you type < then it adds > immediately similarly for quotes and other special paired characters.

As an aside, In Basic and some other programming languages <> can mean "not equal to".
 
jedishrfu said:
My guess is the editor used to create the page had an auto completion feature meaning when you type < then it adds > immediately similarly for quotes and other special paired characters.

As an aside, In Basic and some other programming languages <> can mean "not equal to".
I'm inclined to agree with Samy_A that the page in question has some typos. This inequality, 1) a < c=""><>, is just gibberish. And the same for the other stuff cited.
 
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jedishrfu said:
My guess is the editor used to create the page had an auto completion feature meaning when you type < then it adds > immediately similarly for quotes and other special paired characters.

As an aside, In Basic and some other programming languages <> can mean "not equal to".
Some code-tagging systems use the two characters to surround a tag, like <s>something expressed</s> will put a "strike through" dash through the tagged expression; that is left arrow, s, right arrow, something expressed, left arrow, forwardslash, right arrow.

Also, as jedishru said, "unequal" between two number or string expressions or variables, for some computer programming languages like BASIC.
 
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