# Should [tag:feynman-integral] be a synonym of [tag:path-integral]?

The question is in the title: I see no benefit from having these two tags for essentially the same concept (particularly as the wiki excerpt refers to the path integral formulation of quantum mechanics, rather than to any more general notion of path integration).

• I agree in general that too close tags should be made synonyms (another example recently mentioned being lower-bounds and inequalities, see meta.mathoverflow.net/a/4907/14094) – YCor Mar 21 at 19:24
• @gvmh: The problem is that the Wiener integral is a "path integral", too; should we make it, too, a synonym of "path-integral"? Furthermore, unlike the Wiener integral, the Feynman integral is not a "true" integral. Organizing MO is important, but we should strive not to be zealous in doing so. I would keep these tags as they are now. – Alex M. Mar 25 at 0:02
• @AlexM.: but then the usage info and tag wiki for path-integral needs to be updated to reflect that greater generality. Currently, it (somewhat vaguely) describes the Feynman path integral. – gmvh Mar 25 at 5:44
• @gmvh: Since there are currently 17 questions tagged with "feynman-integral" and only 5 tagged with "path-integral" (of which one is about the Wiener measure!), I would make "path-integral" a synonym of "feynman-integral" and I would merge the tag information and tag wiki of "path-integral" into the tag information and tag wiki of "feynman-integral" (with the necessary modifications, of course). – Alex M. Mar 25 at 8:12
• @gmvh: But! There is a "but"! Feynman integrals are "integrals" over spaces of paths only in quantum mechanics. In quantum field theory, they are "integrals" over spaces of fields, so in this case the connection with the "paths" breaks down. This is why I suggest to leave things as they are (and I shall maybe post this as an answer). – Alex M. Mar 25 at 8:14

• But fields on $\mathbb{R}^{n+1}$ are also paths, viz. in the space of fields on $\mathbb{R}^n$. – gmvh Mar 28 at 14:29
• First, nobody that I know in this area thinks about fields in the way suggested by you. Second, quantum field theory can be studied on space-times that are not necessarily products of the form "space $\times$ time". – Alex M. Mar 28 at 15:46