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How to denote a dummy function argument?
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Peng Yu
Jul 19, 2012, 10:42:20 AM7/19/12
to
Hi,
To denote a function, I can use $f(x)$, where $x$ is a dummy argument,
meaning that I can write it differently like $f(z)$ without the
changing the meaning of $f$. Let's call such argument the dummy
argument of a function.
Since any symbol can be used for dummy argument, I want use some
symbol to explicitly express the "dummy" property of the argument. I
can use $f(.)$, where the dot denotes the dummy argument. But I'm not
sure this is the best and I can't find the best way to typeset a
function with dummy argument in latex. Does anybody have suggestions?
Regards,
Peng
To denote a function, I can use $f(x)$, where $x$ is a dummy argument,
meaning that I can write it differently like $f(z)$ without the
changing the meaning of $f$. Let's call such argument the dummy
argument of a function.
Since any symbol can be used for dummy argument, I want use some
symbol to explicitly express the "dummy" property of the argument. I
can use $f(.)$, where the dot denotes the dummy argument. But I'm not
sure this is the best and I can't find the best way to typeset a
function with dummy argument in latex. Does anybody have suggestions?
Regards,
Peng
Lars Madsen
Jul 19, 2012, 10:47:03 AM7/19/12
to
for example if the function is the absolute value:
|\cdot| : R \to [0,\infty)
--
/daleif (remove RTFSIGNATURE from email address)
Memoir and mh bundle maintainer
LaTeX FAQ: http://www.tex.ac.uk/faq
LaTeX book: http://math.au.dk/videnudveksling/latex/bog/ (in Danish)
Remember to post minimal examples, see URL below
http://www.minimalbeispiel.de/mini-en.html
Lee Rudolph
Jul 19, 2012, 1:01:41 PM7/19/12
to
Lars Madsen <dal...@RTFMSIGNATUREimf.au.dk> writes:
>Peng Yu wrote, On 2012-07-19 16:42:
>> Hi,
>>
>> To denote a function, I can use $f(x)$, where $x$ is a dummy argument,
>> meaning that I can write it differently like $f(z)$ without the
>> changing the meaning of $f$. Let's call such argument the dummy
>> argument of a function.
>>
>> Since any symbol can be used for dummy argument, I want use some
>> symbol to explicitly express the "dummy" property of the argument. I
>> can use $f(.)$, where the dot denotes the dummy argument. But I'm not
>> sure this is the best and I can't find the best way to typeset a
>> function with dummy argument in latex. Does anybody have suggestions?
>>
>> Regards,
>> Peng
>
>I've seen people use \cdot or -
>
>for example if the function is the absolute value:
>
>|\cdot| : R \to [0,\infty)
Yes, \cdot is quite standard, and an en-dash (not a
>Peng Yu wrote, On 2012-07-19 16:42:
>> Hi,
>>
>> To denote a function, I can use $f(x)$, where $x$ is a dummy argument,
>> meaning that I can write it differently like $f(z)$ without the
>> changing the meaning of $f$. Let's call such argument the dummy
>> argument of a function.
>>
>> Since any symbol can be used for dummy argument, I want use some
>> symbol to explicitly express the "dummy" property of the argument. I
>> can use $f(.)$, where the dot denotes the dummy argument. But I'm not
>> sure this is the best and I can't find the best way to typeset a
>> function with dummy argument in latex. Does anybody have suggestions?
>>
>> Regards,
>> Peng
>
>I've seen people use \cdot or -
>
>for example if the function is the absolute value:
>
>|\cdot| : R \to [0,\infty)
hyphen, in my experience) as well; the latter is
also (at least in some fields) used for "dummy
subscripts", e.g., pr_{--} to denote the generic
form of pr_{A} (meaning, perhaps, "projection
onto A").
The intellectually rigorous solution, of course,
would be to use the notation of the lambda
calculus...
Lee Rudolph
Dan
Jul 19, 2012, 2:54:33 PM7/19/12
to
On Jul 19, 12:01 pm, Lee Rudolph <lrudo...@panix.com> wrote:
> Lars Madsen <dal...@RTFMSIGNATUREimf.au.dk> writes:
> >Peng Yu wrote, On 2012-07-19 16:42:
> >> Hi,
>
> >> To denote a function, I can use $f(x)$, where $x$ is a dummy argument,
> >> meaning that I can write it differently like $f(z)$ without the
> >> changing the meaning of $f$. Let's call such argument the dummy
> >> argument of a function.
>
> >> Since any symbol can be used for dummy argument, I want use some
> >> symbol to explicitly express the "dummy" property of the argument. I
> >> can use $f(.)$, where the dot denotes the dummy argument. But I'm not
> >> sure this is the best and I can't find the best way to typeset a
> >> function with dummy argument in latex. Does anybody have suggestions?
>
> Lars Madsen <dal...@RTFMSIGNATUREimf.au.dk> writes:
> >Peng Yu wrote, On 2012-07-19 16:42:
> >> Hi,
>
> >> To denote a function, I can use $f(x)$, where $x$ is a dummy argument,
> >> meaning that I can write it differently like $f(z)$ without the
> >> changing the meaning of $f$. Let's call such argument the dummy
> >> argument of a function.
>
> >> Since any symbol can be used for dummy argument, I want use some
> >> symbol to explicitly express the "dummy" property of the argument. I
> >> can use $f(.)$, where the dot denotes the dummy argument. But I'm not
> >> sure this is the best and I can't find the best way to typeset a
> >> function with dummy argument in latex. Does anybody have suggestions?
>
> >I've seen people use \cdot or -
>
> >for example if the function is the absolute value:
>
> >|\cdot| : R \to [0,\infty)
>
> Yes, \cdot is quite standard, and an en-dash (not a
> hyphen, in my experience) as well; the latter is
> also (at least in some fields) used for "dummy
> subscripts", e.g., pr_{--} to denote the generic
> form of pr_{A} (meaning, perhaps, "projection
> onto A").
$pr_{--}$ produces 2 minus signs. If you want an endash,
>
> >for example if the function is the absolute value:
>
> >|\cdot| : R \to [0,\infty)
>
> Yes, \cdot is quite standard, and an en-dash (not a
> hyphen, in my experience) as well; the latter is
> also (at least in some fields) used for "dummy
> subscripts", e.g., pr_{--} to denote the generic
> form of pr_{A} (meaning, perhaps, "projection
> onto A").
use \text{\textendash} or just \text{--} (assuming amsmath).
Or $pr_{\mbox{--}}$.
(Also, with amsmath loaded, write \DeclareMathOperator\pr{pr}
and use "\pr" instead of just "pr".)
Dan
Lee Rudolph
Jul 19, 2012, 3:43:29 PM7/19/12
to
Dan <luec...@uark.edu> writes:
[I wrote, carelessly:]
to the original poster, in case (momentarily) he was silly
enough to take my post at face value.
Actually, in the case in question, I would presumably
want to define \pr to take an argument (which could be
\text{--} or A or whatever).
Lee Rudolph
[I wrote, carelessly:]
>> Yes, \cdot is quite standard, and an en-dash (not a
>> hyphen, in my experience) as well; the latter is
>> also (at least in some fields) used for "dummy
>> subscripts", e.g., pr_{--} to denote the generic
>> form of pr_{A} (meaning, perhaps, "projection
>> onto A").
>
>$pr_{--}$ produces 2 minus signs. If you want an endash,
>use \text{\textendash} or just \text{--} (assuming amsmath).
>Or $pr_{\mbox{--}}$.
>
>(Also, with amsmath loaded, write \DeclareMathOperator\pr{pr}
>and use "\pr" instead of just "pr".)
Of course, on all counts. Very careless of me; apologies
>> hyphen, in my experience) as well; the latter is
>> also (at least in some fields) used for "dummy
>> subscripts", e.g., pr_{--} to denote the generic
>> form of pr_{A} (meaning, perhaps, "projection
>> onto A").
>
>$pr_{--}$ produces 2 minus signs. If you want an endash,
>use \text{\textendash} or just \text{--} (assuming amsmath).
>Or $pr_{\mbox{--}}$.
>
>(Also, with amsmath loaded, write \DeclareMathOperator\pr{pr}
>and use "\pr" instead of just "pr".)
to the original poster, in case (momentarily) he was silly
enough to take my post at face value.
Actually, in the case in question, I would presumably
want to define \pr to take an argument (which could be
\text{--} or A or whatever).
Lee Rudolph
Joel C. Salomon
Jul 24, 2012, 12:35:13 AM7/24/12
to
On 07/19/2012 01:01 PM, Lee Rudolph wrote:
>> Peng Yu wrote, On 2012-07-19 16:42:
>>> To denote a function, I can use $f(x)$, where $x$ is a dummy argument,
>>> meaning that I can write it differently like $f(z)$ without the
>>> changing the meaning of $f$. Let's call such argument the dummy
>>> argument of a function.
>
>> Peng Yu wrote, On 2012-07-19 16:42:
>>> To denote a function, I can use $f(x)$, where $x$ is a dummy argument,
>>> meaning that I can write it differently like $f(z)$ without the
>>> changing the meaning of $f$. Let's call such argument the dummy
>>> argument of a function.
>
> The intellectually rigorous solution, of course,
> would be to use the notation of the lambda
> calculus...
Or, defining x:R->R to be the identity function on R (or whatever the
> would be to use the notation of the lambda
> calculus...
domain is), you get f(x) == f \circ x == f. The common, sloppy,
notation can be rigorous, too. :)
--Joel
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