We prove that every finite partition of $\omega$ admit an infinite subset that does not compute a Schnorr random real. We use this result to answer two questions of Brendle, Brooke-Taylor, Ng and Nies and strength a result of Khan and Miller.

Lu Liu

High-performance quantum light sources based on semiconductor quantum dots coupled to microcavities are showing their promise in long-distance solid-state quantum networks.

Chao-Yang Lu Jian-Wei Pan

We give a more coherent definition of upward planar order.

Ting Li Xuexing Lu

Two theorems announced by Topkis about the topological description of sublattices are proved. They are applied to extend some classical results concerning the existence and the order structure of Nash equilibria of certain supermodular games, with some problems in Zhou's proof corrected.

Lu Yu

We prove three results on the existence and structure of Nash equilibria for quasisupermodular games. A theorem is purely order-theoretic, and the other two involve topological hypotheses. Our topological results genralize Zhou's theorem (for supermodular games) and Calciano's theorem.

Lu Yu

To generalize complementarities for games, we introduce some conditions weaker than quasisupermodularity and the single crossing property. We prove that the Nash equilibria of a game satisfying these conditions form a nonempty complete lattice. This is a purely order-theoretic generalization of Zhou's theorem.

Lu Yu

If $A$ is an n-by-n matrix over a field $F$ ($A\in M_{n}(F)$), then $A$ is said to ``have an LU factorization'' if there exists a lower triangular matrix $L\in M_{n}(F)$ and an upper triangular matrix $U\in M_{n}(F)$ such that $$A=LU.$$ We give necessary and sufficient conditions for LU factorability of a matrix. Also simple algorithm for computing an LU factorization is given. It is an extension of the Gaussian elimination algorithm to the case of not necessarily invertible matrices. We consider possibilities to factors a matrix that does not have an LU factorization as the product of an ``almost lower triangular'' matrix and an ``almost upper triangular'' matrix. There are many ways to formalize what almost means. We consider some of them and derive necessary and sufficient conditions. Also simple algorithms for computing of an ``almost LU factorization'' are given.

Pavel Okunev Charles R. Johnson

We establish the canonical class inequality for families of higher dimensional projective manifolds. As an application, we get a new inequality between the Chern numbers of 3-folds with smooth families of minimal surfaces of general type over a curve, $c_1^3<18c_3$.

Jun Lu Sheng-Li Tan Kang Zuo

We get a new inequality on the Hodge number $h^{1,1}(S)$ of fibred algebraic complex surfaces $S$, which is a generalization of an inequality of Beauville. Our inequality implies the Arakelov type inequalities due to Arakelov, Faltings, Viehweg and Zuo, respectively.

Jun Lu Sheng-Li Tan Fei Yu Kang Zuo

Delamination strength of REBCO is very important for its applications in large magnet projects. This work presented the transmission electron microscopy (TEM) investigation of the microstructures of the REBCO coated conductor to understand its delamination property. We found that the low delamination strength is associated with nano-voids formed at the IBAD MgO/Y2O3 interface.

Yan Xin Jun Lu Ke Han