10,874 research outputs found
Lattice uniformities inducing unbounded convergence
A net in a locally solid Riesz space
is said to be unbounded -convergent to if
for all . We recall that there is a locally solid linear topology
on such that unbounded -convergence coincides with
-convergence, and moreover, is
characterised as the weakest locally solid linear topology which coincides with
on all order bounded subsets. It is with this motivation that we
introduce, for a uniform lattice , the weakest lattice uniformity
on that coincides with on all the order bounded subsets of
. It is shown that if is the uniformity induced by the topology of a
locally solid Riesz space , then the -topology coincides with
. This allows comparing the results of this paper with
earlier results on unbounded -convergence. It will be seen that despite
the fact that in the setup of uniform lattices most of the machinery used in
the techniques of [M. A. Taylor 2019: Unbounded topologies and uo-convergence
in locally solid vector spaces, J. Math. Anal. Appl. \bf{472} no.1, 981--1000]
is lacking, the concept of `unbounded convergence' well fittingly generalizes
to uniform lattices. We shall also answer Questions 2.13, 3.3, 5.10 of [M. A.
Taylor 2019: Unbounded topologies and uo-convergence in locally solid vector
spaces, J. Math. Anal. Appl. \bf{472} no.1, 981--1000] and Question 18.51 of
[M. A. Taylor 2018: Unbounded convergence in vector lattices, Thesis University
of Alberta].Comment: 19 page
Realization of Rectangular Artificial Spin Ice and Direct Observation of High Energy Topology
In this letter, we have constructed and experimentally investigated
frustrated arrays of dipoles forming two-dimensional artificial spin ices with
different lattice parameters (rectangular arrays with horizontal and vertical
lattice spacings denoted by and respectively). Arrays with three
different ratios , and are
studied. Theoretical calculations of low-energy demagnetized configurations for
these same parameters are also presented. Experimental data for demagnetized
samples confirm most of the theoretical results. However, the highest energy
topology (doubly-charged monopoles) does not emerge in our theoretical model,
while they are seen in experiments for large enough . Our results also
insinuate that magnetic monopoles may be almost free in rectangular lattices
with a critical ratio , supporting previous
theoretical predictions
The mechanical response of cellular materials with spinodal topologies
The mechanical response of cellular materials with spinodal topologies is
numerically and experimentally investigated. Spinodal microstructures are
generated by the numerical solution of the Cahn-Hilliard equation. Two
different topologies are investigated: "solid models," where one of the two
phases is modeled as a solid material and the remaining volume is void space;
and "shell models," where the interface between the two phases is assumed to be
a solid shell, with the rest of the volume modeled as void space. In both
cases, a wide range of relative densities and spinodal characteristic feature
sizes are investigated. The topology and morphology of all the numerically
generated models are carefully characterized to extract key geometrical
features and ensure that the distribution of curvatures and the aging law are
consistent with the physics of spinodal decomposition. Finite element meshes
are generated for each model, and the uniaxial compressive stiffness and
strength are extracted. We show that while solid spinodal models in the density
range of 30-70% are relatively inefficient (i.e., their strength and stiffness
exhibit a high-power scaling with relative density), shell spinodal models in
the density range of 0.01-1% are exceptionally stiff and strong. Spinodal shell
materials are also shown to be remarkably imperfection insensitive. These
findings are verified experimentally by in-situ uniaxial compression of
polymeric samples printed at the microscale by Direct Laser Writing (DLW). At
low relative densities, the strength and stiffness of shell spinodal models
outperform those of most lattice materials and approach theoretical bounds for
isotropic cellular materials. Most importantly, these materials can be produced
by self-assembly techniques over a range of length scales, providing unique
scalability
Vector lattices with a Hausdorff uo-Lebesgue topology
We investigate the construction of a Hausdorff uo-Lebesgue topology on a
vector lattice from a Hausdorff (o)-Lebesgue topology on an order dense ideal,
and what the properties of the topologies thus obtained are. When the vector
lattice has an order dense ideal with a separating order continuous dual, it is
always possible to supply it with such a topology in this fashion, and the
restriction of this topology to a regular sublattice is then also a Hausdorff
uo-Lebesgue topology. A regular vector sublattice of
for a semi-finite measure falls into this
category, and the convergence of nets in its Hausdorff uo-Lebesgue topology is
then the convergence in measure on subsets of finite measure. When a vector
lattice not only has an order dense ideal with a separating order continuous
dual, but also has the countable sup property, we show that every net in a
regular vector sublattice that converges in its Hausdorff uo-Lebesgue topology
always contains a sequence that is uo-convergent to the same limit. This
enables us to give satisfactory answers to various topological questions about
uo-convergence in this context.Comment: 37 pages. Minor changes; a few references added. Final version, to
appear in J. Math. Anal. App
A view of canonical extension
This is a short survey illustrating some of the essential aspects of the
theory of canonical extensions. In addition some topological results about
canonical extensions of lattices with additional operations in finitely
generated varieties are given. In particular, they are doubly algebraic
lattices and their interval topologies agree with their double Scott topologies
and make them Priestley topological algebras.Comment: 24 pages, 2 figures. Presented at the Eighth International Tbilisi
Symposium on Language, Logic and Computation Bakuriani, Georgia, September
21-25 200
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