Wolfram's MathWorld website, at the page on functions, makes the following claim about the notation $f(x)$ for a function:

While this notation is deprecated by professional mathematicians, it is the more familiar one for most nonprofessionals.

From context, it appears that this is referring to the use of $f(x)$ to refer to *the actual function*, rather than just to a particular value, when $x$ is (in the context) a dummy variable.

Is this true? Do professional mathematicians "deprecate" this notation?

To avoid long and windy discussions as to the values or otherwise of this notation (which would be much more appropriate in a blog), this question should be viewed as a poll. As MO runs on StackExchange 1.0, it doesn't have the feature whereby the actual "up" and "down" votes for an answer can be easily seen. Therefore I shall post two answers, one in favour and one against, the following statement. Please **only vote up**. A vote for one answer will be taken as a vote against the other. The Law of the Excluded Middle does not hold here. The motion is:

This house believes that the notation $f(x)$ to refer to a function has value in professional mathematics and that there is no need to apologise or feel embarrassed when using it thus.

**This poll has now run its course. The final tally can be seen below.**

mightmake sense to keep this question open. Although mathematicians may know when to trust the Wolfram site and when not to, I think the site has credibility in the general population as Wolfram is the producer of a popular mathematics software package. So this thread would have something of an "outreach" role, at least as a rebuttal to the statement "depreciated by professional mathematicians". This is definately a borderline question though so I have no strong feelings either way. $\endgroup$ – Ryan Budney Oct 1 '10 at 4:47