36,348 research outputs found
Chromatic number of Euclidean plane
If the chromatic number of Euclidean plane is larger than four, but it is
known that the chromatic number of planar graphs is equal to four, then how
does one explain it? In my opinion, they are contradictory to each other. This
idea leads to confirm the chromatic number of the plane about its exact value
M-estimation in high-dimensional linear model
We mainly study the M-estimation method for the high-dimensional linear
regression model, and discuss the properties of M-estimator when the penalty
term is the local linear approximation. In fact, M-estimation method is a
framework, which covers the methods of the least absolute deviation, the
quantile regression, least squares regression and Huber regression. We show
that the proposed estimator possesses the good properties by applying certain
assumptions. In the part of numerical simulation, we select the appropriate
algorithm to show the good robustness of this methodComment: 16 pages,3 table
Can Up FCNC solve the puzzle?
We investigate the attempt using flavor violation gauge interaction in the up
sector to explain the LHCb recently observed large
(). We study an
Abelian model that only right-handed up quarks is charged under it and the 1-3
coupling is maximized. The simultaneous 1-3 2-3 mixing is realized by a quark
mixing of 1-2 generation. Given the easy identification of top quark, the model
can be directly tested by and processes at the hadron
colliders as associated top production or same-sign top
scattering . The direct search bounds are still consistent with the
assumption that and couplings are equal but the same-sign top
scattering bound is expected to be reached very soon. However, since there is
no CKM-like suppression, the corresponding parameter space for generating
is completely excluded by the mixing. We
conclude that the up FCNC type models cannot explain the while
to be consistent with the mixing constraint at the same
time. On the other hand, a model as SM with fourth family extension has better
chance to explain the large consistently.Comment: 10 pages, 2 figure
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