430 research outputs found
Poset modules of the -Hecke algebras and related quasisymmetric power sum expansions
Duchamp--Hivert--Thibon introduced the construction of a right
-module, denoted as , for any partial order on the set .
This module is defined by specifying a suitable action of on the set
of linear extensions of . In this paper, we refer to this module as the
poset module associated with . Firstly, we show that has a Hopf algebra structure that is isomorphic to the
Hopf algebra of quasisymmetric functions, where is the full
subcategory of whose objects are direct sums of finitely
many isomorphic copies of poset modules and is the
Grothendieck group of . We also demonstrate how
(anti-)automorphism twists interact with these modules, the induction product
and restrictions. Secondly, we investigate the (type 1) quasisymmetric power
sum expansion of some quasi-analogues of Schur functions, where
is a composition. We show that they can be expressed as the sum of the
-partition generating functions of specific posets, which allows us to
utilize the result established by Liu--Weselcouch. Additionally, we provide a
new algorithm for obtaining these posets. Using these findings, for the dual
immaculate function and the extended Schur function, we express the
coefficients appearing in the quasisymmetric power sum expansions in terms of
border strip tableaux.Comment: 42 page
The projective cover of tableau-cyclic indecomposable -modules
Let be a composition of and a permutation in
. This paper concerns the projective covers of
-modules , and
, which categorify the dual immaculate
quasisymmetric function, the extended Schur function, and the quasisymmetric
Schur function when is the identity, respectively. First, we show that
the projective cover of is the projective indecomposable
module due to Norton, and and the -twist
of the canonical submodule of
for 's satisfying suitable
conditions appear as -homomorphic images of .
Second, we introduce a combinatorial model for the -twist of
and derive a series of surjections starting from
to the -twist of
. Finally, we construct the projective
cover of every indecomposable direct summand of
. As a byproduct, we give a characterization of
triples such that the projective cover of
is indecomposable.Comment: 41 page
Homological properties of 0-Hecke modules for dual immaculate quasisymmetric functions
Let be a nonnegative integer. For each composition of , Berg
introduced a cyclic indecomposable -module
with a dual immaculate quasisymmetric function as the
image of the quasisymmetric characteristic. In this paper, we study
's from the homological viewpoint. To be precise, we
construct a minimal projective presentation of and a
minimal injective presentation of as well. Using them, we
compute and , where is
the simple -module attached to a composition of . We also
compute when
and , where represents the lexicographic
order on compositions.Comment: 44 pages, to be published in Forum of Math: Sigm
Management of DiffServ-over-MPLS Transit Networks with BFD/OAM in ForCES Architecture †
Abstract. This paper proposes a management of DiffServ-over-MPLS transit network with BFD(Bidirectional Forwarding Detection)/OAM (operation, administration and maintenance) in ForCES (Forwarding and Control Element Separation) architecture for QoS-guaranteed DiffServ-over-MPLS traffic engineering. The proposed BFD and ForCES functions are implemented on Intel 2400 network processor, where BFD/OAM packets for MPLS TE-LSP are exchanged every 5 ~ 10 ms interval for performance measurements and link failure detection. The operations of BFD/OAM-based fault detection and performance measurement are controlled via distributed control plane with ForCES (forwarding and control element separation) architecture for large scale IP/MPLS router using multiple network processors in each network interface card. We explain the implementation details of ForCES-based distributed control plane functions, hierarchical traffic grooming with label stacking, and BFD/OAM mechanisms. The link failure detection performance of BFD/OAM functions for MPLS TE-LSP is evaluated
Observation of First-Order Metal-Insulator Transition without Structural Phase Transition in VO_2
An abrupt first-order metal-insulator transition (MIT) without structural
phase transition is first observed by current-voltage measurements and
micro-Raman scattering experiments, when a DC electric field is applied to a
Mott insulator VO_2 based two-terminal device. An abrupt current jump is
measured at a critical electric field. The Raman-shift frequency and the
bandwidth of the most predominant Raman-active A_g mode, excited by the
electric field, do not change through the abrupt MIT, while, they, excited by
temperature, pronouncedly soften and damp (structural MIT), respectively. This
structural MIT is found to occur secondarily.Comment: 4 pages, 4 figure
Association between volume status assessed by bioelectrical impedance analysis, lung ultrasound, or weight change and mortality in patients with sepsis-associated acute kidney injury receiving continuous kidney replacement therapy
Background Fluid overload is an independent risk factor of mortality in patients with acute kidney injury (AKI) receiving continuous kidney replacement therapy (CKRT). However, the association between fluid status, as assessed by bioelectrical impedance analysis (BIA) or lung ultrasound, and survival in patients with AKI requiring CKRT has not been established. Methods We analyzed 36 participants with sepsis-associated AKI who received CKRT at a tertiary hospital. The main exposures were volume surrogates: 1) overhydration normalized by extracellular water (OH/ECW, L/L) assessed by BIA, 2) the number of B-lines measured by lung ultrasound, and 3) weight change ([body weight at CKRT initiation – body weight at admission] × 100/body weight at admission). The primary outcome was the 28-day mortality. Results Seventeen participants (47.2%) died within 28 days. There were no significant correlations between OH/ECW and weight change (R2 = 0.040, p = 0.24), number of B-lines and OH/ECW (R2 = 0.056, p = 0.16), or weight change and number of B-lines (R2 = 0.014, p = 0.49). Kaplan-Meier analyses revealed that patients in the highest tertile of OH/ECW showed a significantly lower cumulative 28-day survival probability than the others (the lowest + middle tertiles). The survival probability of participants in the highest tertile of the number of B-lines or weight change did not differ from that of their counterparts. In a multivariate Cox proportional hazard model, the hazard ratio for the highest tertile of OH/ECW was 3.83 (95% confidence interval, 1.04–14.03). Conclusion Volume overload assessed using BIA (OH/ECW) was associated with the 28-day survival rate in patients with sepsis-associated AKI who received CKRT
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