47,752 research outputs found
Homomorphic encryption and some black box attacks
This paper is a compressed summary of some principal definitions and concepts
in the approach to the black box algebra being developed by the authors. We
suggest that black box algebra could be useful in cryptanalysis of homomorphic
encryption schemes, and that homomorphic encryption is an area of research
where cryptography and black box algebra may benefit from exchange of ideas
Representation Theory of Finite Semigroups over Semirings
We develop the representation theory of a finite semigroup over an arbitrary
commutative semiring with unit, in particular classifying the irreducible and
minimal representations. The results for an arbitrary semiring are as good as
the results for a field. Special attention is paid to the boolean semiring,
where we also characterize the simple representations and introduce the
beginnings of a character theory
Tribimaximal Mixing From Small Groups
Current experimental data on the neutrino parameters is in good agreement
with tribimaximal mixing and may indicate the presence of an underlying family
symmetry. For 76 flavor groups, we perform a systematic scan for models: The
particle content is that of the Standard Model plus up to three flavon fields,
and the effective Lagrangian contains all terms of mass dimension <=6. We find
that 44 groups can accommodate models that are consistent with experiment at 3
sigma, and 38 groups can have models that are tribimaximal. For one particular
group, we look at correlations between the mixing angles and make a prediction
for theta13 that will be testable in the near future. We present the details of
a model with theta12=33.9, theta23=40.9, theta13=5.1 to show that the recent
tentative hints of a non-zero theta13 can easily be accommodated. The smallest
group for which we find tribimaximal mixing is T7. We argue that T7 and T13 are
as suited to produce tribimaximal mixing as A4 and should therefore be
considered on equal footing. In the appendices, we present some new
mathematical methods and results that may prove useful for future model
building efforts.Comment: 44 pages, 7 figures. Typos corrected, references added, figures
update
Black Box White Arrow
The present paper proposes a new and systematic approach to the so-called
black box group methods in computational group theory. Instead of a single
black box, we consider categories of black boxes and their morphisms. This
makes new classes of black box problems accessible. For example, we can enrich
black box groups by actions of outer automorphisms.
As an example of application of this technique, we construct Frobenius maps
on black box groups of untwisted Lie type in odd characteristic (Section 6) and
inverse-transpose automorphisms on black box groups encrypting .
One of the advantages of our approach is that it allows us to work in black
box groups over finite fields of big characteristic. Another advantage is
explanatory power of our methods; as an example, we explain Kantor's and
Kassabov's construction of an involution in black box groups encrypting .
Due to the nature of our work we also have to discuss a few methodological
issues of the black box group theory.
The paper is further development of our text "Fifty shades of black"
[arXiv:1308.2487], and repeats parts of it, but under a weaker axioms for black
box groups.Comment: arXiv admin note: substantial text overlap with arXiv:1308.248
Extending tensors on polar manifolds
Let be a Riemannian manifold with a polar action by the Lie group ,
with section and generalized Weyl group . We show that
restriction to is a surjective map from the set of smooth
-invariant tensors on onto the set of smooth -invariant tensors on
. Moreover, we show that every smooth -invariant Riemannian metric
on can be extended to a smooth -invariant Riemannian metric on
with respect to which the -action remains polar with the same section
.Comment: arXiv admin note: text overlap with arXiv:1205.476
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