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Real-analytic manifolds as algebraifolds

Establish whether, for any real-analytic manifold M, the R-algebra C^\omega(M) of real-analytic functions is an R-algebraifold; equivalently, show that the C^\omega(M)-module of R-derivations Der_R(C^\omega(M)) is finitely generated projective.

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Background

For open subsets of \mathbb{R}n, derivations of C\omega(\mathbb{R}n) are given by real-analytic vector fields, and the module is free of rank n. The paper cites results indicating that for a real-analytic manifold M, Der_R(C\omega(M)) corresponds to real-analytic vector fields.

However, the authors do not yet have a proof that this derivation module is finitely generated projective over C\omega(M) for general M, which is needed to conclude that C\omega(M) is an algebraifold.

References

It therefore seems plausible that C\omega(M) is an R-algebraifold as well, but we have not yet been able to prove this.

Differential geometry and general relativity with algebraifolds (2403.06548 - Fritz, 11 Mar 2024) in Section “Examples of algebraifolds and standard form”