# Should questions about the first use of a notation be on topic?

There's been some disagreement on the topicality of "Where do Feynman Diagrams Appear for the first time?", so I wanted to bring the issue to meta to get input from the community. It could be considered a historical question, which speaks to it being off topic, but it's also asking for the work which introduced a specific notation, which is (at least quite close to) what the was created for, and I would say that speaks to it being on topic. What does the community think about this question and others like it which ask for the first work to use a certain kind of notation? Should such questions be on topic?

To guide the discussion, here are three possible outcomes I anticipate (but other options are certainly welcome):

• We could decide that questions of the form "What was the first paper/book/etc. to use [notation]?" are, in general, on topic (and should be tagged ).
• We could decide that questions of the form "What was the first paper/book/etc. to use [notation]?" are off topic, but questions of the form "What paper announced the discovery of [phenomenon]?" remain on topic (and should be tagged ).
• Diverging somewhat from the main question, we could decide to make all questions of the form "What was the first paper/book/etc. to [do X]?" for any X off topic. That would be a change in the scope of the site - basically we'd be rendering the primary use of obsolete.
• Changing 'phenomenon' for 'tool' in your second bullet point, it sounds like in that specific case the decision hinges on whether Feynman diagrams are notation vs tools. I would strongly lean towards the latter. – Emilio Pisanty Oct 8 '17 at 10:23

## 2 Answers

I believe it should be on-topic.

It's a fine line, but I think the request for a paper which first uses a certain notation is pretty much exactly what the tag was for, so I think it'd be kind of inconsistent to make it off-topic but a specific discovery on-topic.

Completely removing as an on-topic subject also doesn't make much sense to me. A final note - this sort of question might be one on topic on both History of Science/Mathematics and here, which isn't necessarily a bad thing.

• What exactly do you mean by "it"? Questions asking for the first introduction of a given concept / tool / formalism / phenomenon, or questions asking about the first use of a given notation? You can have a perfectly functional specific-reference tag for the former while still sending the later to HSM. – Emilio Pisanty Oct 9 '17 at 14:22
• @EmilioPisanty I'd say both =) – heather Oct 9 '17 at 20:31
• +1, especially for "this sort of question might be one on topic on both History of Science/Mathematics and here, which isn't necessarily a bad thing." – Nathaniel Oct 15 '17 at 6:56

I concur with @heather's answer that it should be on topic.

Moreover, I think that whenever we have a meta question along the lines of:

Should this incredibly specific, very low volume class of questions be on topic?

The answer should be yes, they are on topic. I'm not really sure what purpose any other answer could serve.