nLab Bochner linearization theorem

This entry is about Bochner’s theorem on transformation groups. For the statement in harmonic analysis see at Bochner's theorem.

Context

Differential geometry

synthetic differential geometry

Introductions

from point-set topology to differentiable manifolds

geometry of physics: coordinate systems, smooth spaces, manifolds, smooth homotopy types, supergeometry

Differentials

V-manifolds

smooth space

Tangency

The magic algebraic facts

Theorems

Axiomatics

cohesion

infinitesimal cohesion

tangent cohesion

differential cohesion

graded differential cohesion

singular cohesion

id id fermionic bosonic bosonic Rh rheonomic reduced infinitesimal infinitesimal & étale cohesive ʃ discrete discrete continuous * \array{ && id &\dashv& id \\ && \vee && \vee \\ &\stackrel{fermionic}{}& \rightrightarrows &\dashv& \rightsquigarrow & \stackrel{bosonic}{} \\ && \bot && \bot \\ &\stackrel{bosonic}{} & \rightsquigarrow &\dashv& \mathrm{R}\!\!\mathrm{h} & \stackrel{rheonomic}{} \\ && \vee && \vee \\ &\stackrel{reduced}{} & \Re &\dashv& \Im & \stackrel{infinitesimal}{} \\ && \bot && \bot \\ &\stackrel{infinitesimal}{}& \Im &\dashv& \& & \stackrel{\text{étale}}{} \\ && \vee && \vee \\ &\stackrel{cohesive}{}& \esh &\dashv& \flat & \stackrel{discrete}{} \\ && \bot && \bot \\ &\stackrel{discrete}{}& \flat &\dashv& \sharp & \stackrel{continuous}{} \\ && \vee && \vee \\ && \emptyset &\dashv& \ast }

Models

Lie theory, ∞-Lie theory

differential equations, variational calculus

Chern-Weil theory, ∞-Chern-Weil theory

Cartan geometry (super, higher)

Representation theory

Contents

Idea

The Bochner linearization theorem [Bochner 1945] states that for a differentiable group action of a compact Lie group on a differentiable manifold there exists around each fixed point a (similarly differentiable) local coordinate chart on which the action is linear.

(The analogous statement for analytic manifolds and analytic group actions is attributed by Bochner 1945 to Henri Cartan, referencing Martin 1944.)

This linearization theorem is the special case (for fixed loci of dimension=0=0) of the existence of equivariant tubular neighbourhoods, see there for more.

References

The original article:

following

  • W. T. Martin: Mappings by means of systems of analytic functions of several complex variables, Bulletin of the American Math. Society 50 1 (1944) 5-19.

See also:

  • Nicolas Bourbaki: Prop. 5 §9.3 Chapter IX, of: Lie Groups and Algebras, Masson (1982), Springer (2007) [scan]

Created on June 14, 2025 at 11:27:24. See the history of this page for a list of all contributions to it.