Koras–Russell cubic threefold
Encyclopedia
In algebraic geometry
, the Koras–Russell cubic threefolds are smooth affine contractible threefolds studied by that have a hyperbolic action of a one-dimensional torus
with a unique fixed point, such that the quotients of the threefold and the tangent space of the fixed point by this action are isomorphic.
Algebraic geometry
Algebraic geometry is a branch of mathematics which combines techniques of abstract algebra, especially commutative algebra, with the language and the problems of geometry. It occupies a central place in modern mathematics and has multiple conceptual connections with such diverse fields as complex...
, the Koras–Russell cubic threefolds are smooth affine contractible threefolds studied by that have a hyperbolic action of a one-dimensional torus
Torus
In geometry, a torus is a surface of revolution generated by revolving a circle in three dimensional space about an axis coplanar with the circle...
with a unique fixed point, such that the quotients of the threefold and the tangent space of the fixed point by this action are isomorphic.