For which undergraduate and graduate mathematics courses is multivariable analysis* an essential prerequisite?
$\text{*}$ That is, a rigorous follow up to a first real analysis course at the level of baby Rudin.
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Sign up to join this communityBy multivariate analysis, I'm assuming that you're talking about a course that covers the following topics in a rigorous way:
Differentiation of functions between vector spaces
The inverse and implicit function theorems, and related topics (e.g. rank of the derivative, immersions and submersions).
Critical points and regular points of multivariable functions
Multiple integrals and some version of Fubini's Theorem
Differential forms and Stokes' Theorem
Possibly an introduction to differentiable manifolds
My opinion is that such a course isn't an essential prerequisite for any later courses, for the simple reason that many (or perhaps most) colleges do not offer a course on multivariate analysis.
That being said, I think such a course would be very helpful for students who are planning to go into geometry, topology, or related subjects. A typical graduate course on differentiable manifolds (out of, say, Lee's Introduction to Smooth Manifolds) covers some of this material very quickly near the beginning, and covers differential forms quickly in the middle and in the more general setting of manifolds. As with many graduate courses, such a course is theoretically self-contained, but it helps a lot to have seen some of the material before. Other graduate courses that use this material might include courses on Riemannian Geometry, Differential Topology, Algebraic Topology (out of, say, Bott and Tu), Lie groups, or even courses on Riemann Surfaces or Algebraic Geometry.
An undergraduate differential geometry course might also assume some of this material, but probably at most on the level of multivariable calculus. For example, it might assume that students have seen the inverse function theorem, but it wouldn't assume that students have seen the proof. This is probably true of almost any undergraduate course.
Motivated by Jim Belk's answer, let me mention that a rigorous advanced PDE course builds heavily on the material you mention. In particular,
"Multivariable analysis" is the key to "advanced calculus." The latter includes (but is not limited to):