Complex Analytic and Formal Solutions of Real Analytic Equations in Cn.
We present a general result on regularization of an arbitrary convex body (and more generally a star body), which gives and extends global forms of a number of well known local facts, like the low M*-estimates, large Euclidean sections of finite volume-ratio spaces and others.
Neither real analytic sets nor the images of real or complex analytic mappings are, in general, coherent. Let be a morphism of real analytic spaces, and let be a homomorphism of coherent modules over the induced ring homomorphism . We conjecture that, despite the failure of coherence, certain natural discrete invariants of the modules of formal relations , , are upper semi-continuous in the analytic Zariski topology of . We prove semicontinuity in many cases (e.g. in the algebraic category)....
This is a sequel to “Relations among analytic functions I”, , , fasc. 1, [pp. 187-239]. We reduce to semicontinuity of local invariants the problem of finding solutions to systems of equations involving division and composition by analytic functions. We prove semicontinuity in several general cases : in the algebraic category, for “regular” mappings, and for module homomorphisms over a finite mapping.
In this note we introduce a notion of essentially-Euclidean normed spaces (and convex bodies). Roughly speaking, an n-dimensional space is λ-essentially-Euclidean (with 0 < λ < 1) if it has a [λn]-dimensional subspace which has further proportional-dimensional Euclidean subspaces of any proportion. We consider a space X₁ = (ℝⁿ,||·||₁) with the property that if a space X₂ = (ℝⁿ,||·||₂) is "not too far" from X₁ then there exists a [λn]-dimensional subspace E⊂ ℝⁿ such that E₁ = (E,||·||₁) and...
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