Isomorphism in expanding families of indistinguishable groups
نویسندگان
چکیده
منابع مشابه
Isomorphism of Borel Full Groups
Suppose that G and H are Polish groups which act in a Borel fashion on Polish spaces X and Y . Let EX G and E Y H denote the corresponding orbit equivalence relations, and [G] and [H] the corresponding Borel full groups. Modulo the obvious counterexamples, we show that [G] ∼= [H] ⇔ EX G ∼=B EY H .
متن کاملOn the Isomorphism of Fundamental Groups
One can prove the following propositions: (1) Let A, B, a, b be sets and f be a function from A into B. If a ∈ A and b ∈ B, then f+·(a7−→ . b) is a function from A into B. (2) For every function f and for all sets X, x such that f↾X is one-to-one and x ∈ rng(f↾X) holds (f · (f↾X)−1)(x) = x. (3) Let x, y, X, Y , Z be sets, f be a function from [:X, Y :] into Z, and g be a function. If Z 6= ∅ and...
متن کاملComputation of Isomorphism Classes of /»-Groups
p-groups may be classified by splitting the groups up into classes having the same commutator relations (isoclinism classes) and then determining the nonisomorphic groups in each class. This paper reduces the problem of determining the isomorphism classes to that of finding the equivalence classes of a set of matrices under some equivalence relation. A computer is used to find the equivalence c...
متن کاملIsomorphism invariants for actions of sofic groups
For every countable group G, a family of isomorphism invariants for measurepreserving G-actions on probability spaces is defined. In the special case in which G is a countable sofic group, a special class of these invariants are computed exactly for Bernoulli systems over G. This leads to a complete classification of Bernoulli systems for many countable groups including all finitely generated l...
متن کاملDefect Groups and the Isomorphism Problem
As a ring, a block may arise from more than one finite group. The resulting conjugacy issue for defect groups is important for the group ring isomorphism problem and for understanding block theory in general. There are even indirect structural consequences for finite groups, through G. Robinson’s work on the “Z-star theorem” for odd primes. A positive answer to the defect group conjugacy proble...
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: Groups - Complexity - Cryptology
سال: 2012
ISSN: 1867-1144,1869-6104
DOI: 10.1515/gcc-2012-0008