Results 61 to 70 of about 13,867 (163)
Completion, extension, factorization, and lifting of operators with a negative index [PDF]
, 2014 The famous results of M.G. Kre\u{\i}n concerning the description of selfadjoint contractive extensions of a Hermitian contraction $T_1$ and the characterization of all nonnegative selfadjoint extensions $\widetilde A$ of a nonnegative operator $A$ via ...
Baidiuk, D., Hassi, S.
core
Stochastic Multiplicative Updates for Symmetric Nonnegative Matrix Factorization
, 2021 Innen maskinlæring brukes symmetrisk ikkenegativ matrisefaktorisering (NMF) i forbindelse med clusteranalyse. NMF utføres ofte ved hjelp av algoritmer som tar i bruk multiplikative oppdateringer (MU). Disse har den fordelen at de automatisk opprettholder ikkenegativitet i faktormatrisen.
Schlüter, Klara, Riege, Jon
openaire +2 more sources
Optimal Portfolio Choice With Cross‐Impact Propagators
Mathematical Finance, EarlyView.ABSTRACT We consider a class of optimal portfolio choice problems in continuous time where the agent's transactions create both transient cross‐impact driven by a matrix‐valued Volterra propagator, as well as temporary price impact. We formulate this problem as the maximization of a revenue‐risk functional, where the agent also exploits available ...
Eduardo Abi Jaber +2 more
wiley +1 more source
Fast and Effective Algorithms for Symmetric Nonnegative Matrix Factorization
, 2016 Symmetric Nonnegative Matrix Factorization (SNMF) models arise naturally as simple reformulations of many standard clustering algorithms including the popular spectral clustering method. Recent work has demonstrated that an elementary instance of SNMF provides superior clustering quality compared to many classic clustering algorithms on a variety of ...
Borhani, Reza +2 more
openaire +2 more sources
Relative Arbitrage Opportunities With Interactions Among N Investors
Mathematical Finance, EarlyView.ABSTRACT The relative arbitrage portfolio outperforms a benchmark portfolio over a given time‐horizon with probability one. With market price of risk processes depending on the market portfolio and investors, this paper analyzes the multi‐agent optimization of relative arbitrage opportunities in the coupled system of market and wealth dynamics.
Tomoyuki Ichiba, Nicole Tianjiao Yang
wiley +1 more source
Descent methods for Nonnegative Matrix Factorization [PDF]
, 2008 In this paper, we present several descent methods that can be applied to nonnegative matrix factorization and we analyze a recently developped fast block coordinate method called Rank-one Residue Iteration (RRI).
Blondel, Vincent D. +2 more
core +2 more sources
The Mathematical History Behind the Granger–Johansen Representation Theorem
Oxford Bulletin of Economics and Statistics, EarlyView.ABSTRACT When can a vector time series that is integrated once (i.e., becomes stationary after taking first differences) be described in error correction form? The answer to this is provided by the Granger–Johansen representation theorem. From a mathematical point of view, the theorem can be viewed as essentially a statement concerning the geometry of ...
Johannes M. Schumacher
wiley +1 more source
Trade and Selection With Heterogeneous Firms and Perfect Competition
Review of International Economics, EarlyView.ABSTRACT This paper extends the Heckscher–Ohlin–Samuelson framework to allow for heterogeneous firms with capacity constraints. We show that the central theorems of the HOS model (as well as their standard generalizations via duality) carry over to our setting.
Xue Bai +3 more
wiley +1 more source
Dimension reduction for optimal design problems with Kronecker product structure
Scandinavian Journal of Statistics, EarlyView.Abstract This paper is motivated by the problem of optimal allocation of trials in multi‐environment crop variety testing with a large number of varieties. Optimizing the allocation of trials results in the minimization of a design criterion with a Kronecker product structure in the information matrix.
Taras Bodnar, Maryna Prus
wiley +1 more source
On the additive image of zeroth persistent homology
Transactions of the London Mathematical Society, Volume 13, Issue 1, December 2026.Abstract For a category X$X$ and a finite field F$F$, we study the additive image of the functor H0(−;F)∗:rep(X,Top)→rep(X,VectF)$\operatorname{H}_0(-;F)_* \colon \operatorname{rep}(X, \mathbf {Top}) \rightarrow \operatorname{rep}(X, \mathbf {Vect}_F)$, or equivalently, of the free functor rep(X,Set)→rep(X,VectF)$\operatorname{rep}(X, \mathbf {Set ...
Ulrich Bauer +3 more
wiley +1 more source