2 citations · 4 across the 7 of their papers we have counts for
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Nilpotency and higher order derivatives in differential geometry
Ercument H. Ortacgil
We give simple upper and lower bounds for the order of a Klein geometry
The canonical geometry of a Lie group
Ercument H. Ortacgil
A Lie group G has many left invariant metrics having drastically different curvature properties. If we regard G as a flat and globalizable absolute parallelism as in [O1], then G h…
Curvature without connection
Ercument H. Ortacgil
We show that the theory of geometric structures proposed in the recent book "An Alternative Approach to Lie Groups and Geometric Structures" can be developed independently of conne…
Riemannian geometry as a curved pre-homogeneous geometry
Ercument Ortacgil
We define a Riemannian structure as a pre-homogeneous geometric structure with curvature R. We show that R=0 if and only if the underlying metric has constant curvature. We define…
Intrinsic characteristic classes for a local Lie group
Ender Abadoglu, Ercument Ortacgil
For a local Lie group M we define odd order cohomology classes. The first class is an obstruction to globalizability of the local Lie group. The third class coincides with Godbillo…
Klein geometries and stable nonlinear Spencer sequence
Ender Abadoglu, Ercument Ortacgil
This paper has been withdrawn by the authors
Klein geometries, parabolic geometries and differential equations of finite type
Ender Abadoglu, Ercument Ortacgil
We define the infinitesimal and geometric orders of an effective Klein geometry G/H. Using these concepts, we prove i) For any integer m>1, there exists an effective Klein geometry…