bio  website  

location  Silesia, Czech Republic  
age  35  
visits  member for  2 years, 6 months 
seen  6 hours ago  
stats  profile views  585 
Reasonably expert in Differential Geometry, I work mostly with jet bundles and their natural structures trying to exploit them in the areas of nonlinear PDEs and Calculus of Variations.
6h

revised 
Extending derivations to the superposition closure
added 787 characters in body 
Oct 7 
revised 
Extending derivations to the superposition closure
added 3 characters in body 
Oct 7 
asked  Extending derivations to the superposition closure 
Oct 4 
accepted  How to “lift” a transitive group action on a manifold? 
Sep 30 
comment 
How to “lift” a transitive group action on a manifold?
@BenMcKay: incidentally, can you always realise $\frak{g}$, the Lie algebra of $G$, as an algebra of vector fields on $M$, i.e., can you embed it into the (infinitedimensional) Lie algebra of vector fields on $M$? 
Sep 30 
comment 
How to “lift” a transitive group action on a manifold?
@VítTuček: yes, actually in the cases I'm interested in, $\widetilde{M}$ is compact. 
Sep 29 
comment 
How to “lift” a transitive group action on a manifold?
Indeed. This is more or less what I suggested in my last lines. I'm aware of LiePalais theorem, though you need to require some extra topological conditions from $\widetilde{M}$. Still, I'd like to see some universal property characterising $\widetilde{G}$, like, e.g., "it is the unique group admitting $G$ as a factor by covering transformations", or something like that, and/or some algebraic way to construct it out of the available data! 
Sep 29 
asked  How to “lift” a transitive group action on a manifold? 
Sep 29 
comment 
What is the most useful nonexisting object of your field?
As a general rule, you appoint a name to something if that thing has been around for a while: even if its existence is disproved later, the name will stick to it. It's a nice phenomenon. Think about the aether: for decades people believed it surrounded us, now we know it cannot exists, but its name persists in SF and fantasy tales! I guess that before Galois the name "general solution for quintic equations" was often used, both by those who believed it existed and it was yet to be found, by those who erroneously believed they found it, and by those who were trying to prove it cannot exists! 
Sep 24 
awarded  Autobiographer 
Sep 9 
accepted  Can the finiteness of a Burnside group with two generators be checked algorithmically by using Fuchsian von Dyck groups? 
Sep 8 
comment 
Can the finiteness of a Burnside group with two generators be checked algorithmically by using Fuchsian von Dyck groups?
Your almost cleared out all my doubts  yet I need time to fully digest your answer. Now, let us focus on your last sentence: "I certainly don't see any particular obstruction to attempting the computation in the case of $B(2,5)$". Believe me, I've been trying for years to find out what is the stateoftheart concerning the finiteness of $B(2,5)$, but in vain. Can you point out somebody to whom I may ask? Why there are a lot of computers employed to discover the 'last' digit of $\pi$, or the 'biggest' prime, but none cares about finiteness of $B(2,5)$? Is there at least the algorithm written? 
Sep 5 
revised 
Can the finiteness of a Burnside group with two generators be checked algorithmically by using Fuchsian von Dyck groups?
Previous question, titled "Coverings of the free Burnside groups", was never answered. So, I reformulate it adding new details I discovered meanwhile. 
Aug 6 
accepted  Is there a “unique” homogeneous contact structure on odddimensional spheres? 
Jul 16 
comment 
Symmetry analysis of differential equations
The standard reference on this concern is Michor's book mat.univie.ac.at/~michor/… Anyway, I would guess that there are only two homotopy types: the orientationpreserving and the orientationreversing. The identical transformation is the diagonal of $\mathbb{R}^2$, and I don't see any reason why it shouldn't be possible to deform the graph of any other orientationpreserving transformation to the diagonal. 
Jul 11 
comment 
Euler Class of a vector field
@HenryT.Horton: why do you need to pass to a 2plane field? Besides, in the question there are no metrics mentioned, so you cannot take "orthogonal"... What about the line bundle spanned by $X$? I think in this case, the Euler class just tells whether $X$ is nowhere vanishing or not (e.g., if I'm not mistaken, on the 2sphere all fields should have nonzero Euler class). 
Jul 9 
answered  Generalized Leibniz rule 
Jul 7 
awarded  Nice Question 
Jul 4 
comment 
Is there a “unique” homogeneous contact structure on odddimensional spheres?
@RobertBryant : following your comment, I added a long edit to the original question. 
Jul 4 
revised 
Is there a “unique” homogeneous contact structure on odddimensional spheres?
Added a long edit following R. Bryant's last remark. 