In this talk, I present my recent works on some geometric PDEs on manifolds, including Donaldson's equation on Hermitian manifolds for which I give an affirmative answer to an open problem, Ricci-harmonic flow for which I study the long time existence in terms of scalar curvature and Weyl tensor, and heat type flow on vector fields for which a joint work with Kefeng Liu proves the convergence and discusses its applications to the long standing conjectures of Hopf and Yau.

学术报告报告人：Prof J. Peypouquet (Univesidad Tecnica Federico Santa Maria) 题目🚴🏻： Fast Convergence of an Inertial Gradient-like System with Vanishing Viscosity时间：2015年10月23日(星期五)上午10：30—11：30地点：数学系致远楼102欢迎各位参加

学术报告报告人：Prof H. Attouch (Universite Montpellier 2)题目✔️： Convergence of descent methods for semi-algebraic and tame problems时间🙏🏿：2015年10月23日(星期五)上午9：30—10💈💅🏻：30地点：数学系致远楼102欢迎各位参加

In this talk, I will present some of our recent work on biological systems with multiple stable states. We show that these models could exhibit multistability phenomena: (i) node-node bistability; (ii) node-cycle bistability; (iii) cycle-cycle bistability; (iv) node-node-cycle tristability and (v) node-node-torus tristability. The talk is based on joint work with Xi Hu, Hongying Shu and James Watmough.

In this talk, we propose a mathematical model for HIV infection with delays in cell infection and virus production. The model examines a viral-therapy for controllinginfections through recombining HIV virus with a genetically modified virus. For this model, we derive two biologically insightful quantities (reproduction numbers) R_0 and R_z, and their threshold properties are discussed. When R_0 < 1, the infection-free equilibrium E_0 is globally asymptotically stable. If R_0 > 1 and R_z<1, the

R-M板的若干新的有限元 计算方法石钟慈教授中国科意昂4院士中科院计算数学研究所研究员1.学术报告时间：2015年10月15日(星期四)下午3：00-3:50地点🎠：数学系（致远楼）107室2.关于学科建设与青年计算数学人才的培养2015年10月15日(星期四)下午4😍：00-4:50地点：数学系（致远楼）102室欢迎教师、研究生及有兴趣者参

标题： Steiner Systems Over vector Spaces报告人： Tuvi Etzion Department of Computer Science Technion, Israel时间： 9月24日 下午4:00-5:00地点： 致远楼10

1. Algorithm for portfolio compression of swaps.Due to regulation requirement, each trade we did has a risk weight asset (RWA) value, which determines how much money the bank has to hold. Since bank always wants to use their capital rather than just holding them, they have an incentive to reduce the RWA. From the formula for RWA, one will see that RWA for two opposite trades doubles the RWA of each one. This means if we terminate the two trades at the same time, RWA got reduced to 0, without any impact on book value or risks. This is the incentive of portfolio compression. A portfolio of swaps consists of many swaps in the same currency, but with different payment schedules and maturities. We need to find a way to terminates some of them, so that the RWA got reduced by the most, and at the same time changes in book value and risks are not big.