Open AccessOn almost complex structures from classical linear connections
Author(s) -
Jan Kurek,
Włodzimierz M. Mikulski
Publication year - 2017
Publication title -
annales universitatis mariae curie-skłodowska. sectio a, mathematica
Language(s) - English
Resource type - Journals
eISSN - 2083-7402
pISSN - 0365-1029
DOI - 10.17951/a.2017.71.1.55
Subject(s) - functor , nabla symbol , mathematics , covariant transformation , covariance and contravariance of vectors , tangent space , combinatorics , vector space , manifold (fluid mechanics) , pure mathematics , physics , geometry , quantum mechanics , mechanical engineering , engineering , omega
Let \(\mathcal{M} f_m\) be the category of \(m\)-dimensional manifolds and local diffeomorphisms and let \(T\) be the tangent functor on \(\mathcal{M} f_m\). Let \(\mathcal{V}\) be the category of real vector spaces and linear maps and let \(\mathcal{V}_m\) be the category of \(m\)-dimensional real vector spaces and linear isomorphisms. We characterize all regular covariant functors \(F:\mathcal{V}_m\to\mathcal{V}\) admitting \(\mathcal{M} f_m\)-natural operators \(\tilde J\) transforming classical linear connections \(\nabla\) on \(m\)-dimensional manifolds \(M\) into almost complex structures \(\tilde J(\nabla)\) on \(F(T)M=\bigcup_{x\in M}F(T_xM)\).