Tangentially biharmonic Lagrangian H-umbilical submanifolds in complex space forms

The notion of Lagrangian $H$-umbilical submanifolds was introduced by B. Y. Chen in 1997, and these submanifolds have appeared in several important problems in the study of Lagrangian submanifolds from the Riemannian geometric point of view. Recently, the author introduced the notion of tangentially biharmonic submanifolds, which are defined as submanifolds such that the bitension field of the inclusion map has vanishing tangential component. The normal bundle of a round hypersphere in $\mathbb{R}^n$ can be immersed as a tangentially biharmonic Lagrangian $H$-umbilical submanifold in $\mathbb{C}^n$. Motivated by this fact, we classify tangentially biharmonic Lagrangian $H$-umbilical submanifolds in complex space forms

Biharmonic C-parallel Legendrian submanifolds in 7-dimensional Sasakian space forms

This paper corrects the classification result for biharmonic C-parallel Legendrian submanifolds presented by D. Fetcu and C. Oniciuc in [Tohoku Math. J. 64 (2012), 195-222].Comment: 10 page

Multiuser Detection by MAP Estimation with Sum-of-Absolute-Values Relaxation

In this article, we consider multiuser detection that copes with multiple access interference caused in star-topology machine-to-machine (M2M) communications. We assume that the transmitted signals are discrete-valued (e.g. binary signals taking values of $\pm 1$), which is taken into account as prior information in detection. We formulate the detection problem as the maximum a posteriori (MAP) estimation, which is relaxed to a convex optimization called the sum-of-absolute-values (SOAV) optimization. The SOAV optimization can be efficiently solved by a proximal splitting algorithm, for which we give the proximity operator in a closed form. Numerical simulations are shown to illustrate the effectiveness of the proposed approach compared with the linear minimum mean-square-error (LMMSE) and the least absolute shrinkage and selection operator (LASSO) methods.Comment: submitted; 6 pages, 7 figure