Learn More
In this article, we consider the conjecture that a Q-homology plane with constant Makar-Limanov invariants is isomorphic to either the affine plane A2 or the complement of a smooth conic on the projective plane P. Though the conjecture is not fully solved yet, we can show strong evidences to support the conjecture. Furthermore, it is shown that such a(More)
The 1-dimensional topological network (line) and 2-dimensional topological network (2D-plane) of self-organizing Maps are well used for many applications. We propose the 3-dimensional topological self-organizing maps and give suggestion of an ability of more higher dimensional Maps. Since a compression ratio becomes low by 3-dimensional SOM as compared with(More)
Iwan Arzhantsev (Moscow State University) Cox rings, universal torsors, and infinite transitivity Let X be an algebraic variety covered by open charts isomorphic to the affine space and let q : X ′ → be the universal torsor over X. We prove that the automorphism group of the quasiaffine variety X ′ acts on X ′ infinitely transitively. Also we find wide(More)
  • 1