A countable Teichmüller modular group
نویسندگان
چکیده
منابع مشابه
Ultra-Countable Functors and Descriptive Group Theory
Let Ȳ be a n-dimensional curve. Is it possible to compute topoi? We show that g̃ = 2. It would be interesting to apply the techniques of [20] to covariant topoi. This reduces the results of [20] to an approximation argument.
متن کاملRauzy fractals with countable fundamental group
We prove that every free group of finite rank can be realized as the fundamental group of a planar Rauzy fractal associated with a 4-letter unimodular cubic Pisot substitution. This characterizes all countable fundamental groups for planar Rauzy fractals. We give an explicit construction relying on two operations on substitutions: symbolic splittings and conjugations by free group automorphisms.
متن کاملEdge-Magic Group Labellings of Countable Graphs
We investigate the existence of edge-magic labellings of countably infinite graphs by abelian groups. We show for that for a large class of abelian groups, including the integers Z, there is such a labelling whenever the graph has an infinite set of disjoint edges. A graph without an infinite set of disjoint edges must be some subgraph of H + I, where H is some finite graph and I is a countable...
متن کاملThe Full Group of a Countable Measurable Equivalence Relation
We study the group of all "R-automorphisms" of a countable equivalence relation R on a standard Borel space, special Borel automorphisms whose graphs lie in R. We show that such a group always contains periodic maps of each order sufficient to generate R . A construction based on these periodic maps leads to totally nonperiodic R-automorphisms all of whose powers have disjoint graphs. The prese...
متن کاملBorel structurability on the 2-shift of a countable group
We show that for any infinite countable group G and for any free Borel action G y X there exists an equivariant class-bijective Borel map from X to the free part Free(2G) of the 2-shift G y 2G. This implies that any Borel structurability which holds for the equivalence relation generated by Gy Free(2G) must hold a fortiori for all equivalence relations coming from free Borel actions of G. A rel...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Transactions of the American Mathematical Society
سال: 2004
ISSN: 0002-9947,1088-6850
DOI: 10.1090/s0002-9947-04-03765-1