C-R Immersions and Sub-Riemannian Geometry

نویسندگان

چکیده

On any strictly pseudoconvex CR manifold M, of dimension n, equipped with a positively oriented contact form θ, we consider natural ϵ-contractions, i.e., contractions gϵM the Levi Gθ, such that norm Reeb vector field T (M, θ) is order O(ϵ−1). We study isopseudohermitian (i.e., f∗Θ=θ) Cauchy–Riemann immersions f:M→(A,Θ) between manifolds M and A, where Θ on A. For every contraction gϵA GΘ, write embedding equations for immersion f:M→A,gϵA. A pseudohermitan version Gauss equation an C-R obtained by elementary asymptotic analysis as ϵ→0+. f:M→S2N+1 into sphere S2N+1⊂CN+1, show Webster’s pseudohermitian scalar curvature R satisfies inequality R≤2n(f∗gΘ)(T,T)+n+1+12{∥H(f)∥gΘf2+∥traceGθΠH(M)∇⊤−∇∥f∗gΘ2} equality if only B(f)=0 ∇⊤=∇ H(M)⊗H(M). This gives analog to classical result S-S. Chern minimal isometric space forms.

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ژورنال

عنوان ژورنال: Axioms

سال: 2023

ISSN: ['2075-1680']

DOI: https://doi.org/10.3390/axioms12040329