# The incorrect tag description of [pochhammer-symbol]

The Pochhammer symbol is the notation used for rising and falling factorials. The $$q$$-Pochhammer symbol is the $$q$$-analog.

To be a $$q$$-analog, the $$q$$-Pochhammer symbol must equal the original expression (rising or falling factorial) as $$q \rightarrow 1$$ (or at least $$q \rightarrow 1^-$$). This is not the case, as is very easy to check. Details in my earlier question here. As I point out there, Wolfram MathWorld and Wikipedia both commit the same error. I'm not sure what the description should be instead, but we can't just have false statements lying around.

• Note the Wikipedia article on q-analog which explains: "q-analogues are most frequently studied in the mathematical fields of combinatorics and special functions. In these settings, the limit q → 1 is often formal, as q is often discrete-valued (for example, it may represent a prime power)." Sep 1, 2019 at 19:05
• Yet nowhere does it say that the limit criterion is not necessary for something to be a $q$-analog. Sep 1, 2019 at 22:29
• As you've posted a Question on the main Math.SE site about the justification for the terminology (or lack thereof), I'll try to address your presumed lack of justification there. Sep 1, 2019 at 22:43

I've edited the tag info for to avoid the problematic claim that $$q$$-Pochhammer symbol is a $$q$$-analog of the Pochhammer symbol.

I'll post a discussion of the history of this "convention" on the Main Math.SE Question, including a link to a previous Question there that discusses the infelicity of such terminology.