Results 61 to 70 of about 546 (144)
The Huang–Yang Formula for the Low‐Density Fermi Gas: Upper Bound
Communications on Pure and Applied Mathematics, Volume 79, Issue 8, Page 1919-1972, August 2026.ABSTRACT We study the ground state energy of a gas of spin 1/2$1/2$ fermions with repulsive short‐range interactions. We derive an upper bound that agrees, at low density ϱ$\varrho$, with the Huang–Yang conjecture. The latter captures the first three terms in an asymptotic low‐density expansion, and in particular the Huang–Yang correction term of order
Emanuela L. Giacomelli +3 more
wiley +1 more source
Intraday Functional PCA Forecasting of Cryptocurrency Returns
Journal of Forecasting, Volume 45, Issue 5, Page 2186-2212, August 2026.ABSTRACT We study the functional PCA (FPCA) forecasting method in application to functions of intraday returns on Bitcoin. We show that improved interval forecasts of future return functions are obtained when the conditional heteroscedasticity of return functions is taken into account.
Joann Jasiak, Cheng Zhong
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四川大学学报. 自然科学版Clustering is an important unsupervised learning technique in machine learning and artificial intelligence.Clustering algorithms can uncover latent structures and patterns from unlabeled data， and provide strong support for subsequent data analysis ...
GAO Hai-Yan, HE Wen-Hui
doaj
Journal of Geophysical Research: Machine Learning and Computation, Volume 3, Issue 4, August 2026.Abstract Accurate forecasting of geomagnetic perturbations is essential for assessing space weather risk of geomagnetic activities. Thanks to decades of magnetometer observations from world‐wide distributed networks and upstream solar wind observations at L1, data‐driven modeling of global geomagnetic perturbations has become increasingly feasible ...
Hongfan Chen +4 more
wiley +1 more source
The Mathematical History Behind the Granger–Johansen Representation Theorem
Oxford Bulletin of Economics and Statistics, Volume 88, Issue 4, Page 587-602, August 2026.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, Volume 34, Issue 3, Page 793-804, August 2026.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
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On the positivity and integrality of coefficients of mirror maps
Bulletin of the London Mathematical Society, Volume 58, Issue 8, August 2026.Abstract We present natural conjectural generalisations of the ‘positivity and integrality of mirror maps’ phenomenon, encompassing the mirror maps appearing in the Batyrev–Borisov construction of mirror Calabi–Yau complete intersections in Fano toric varieties as a special case.
Sophie Bleau, Nick Sheridan
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Fine multidegrees, universal Gröbner bases, and matrix Schubert varieties
Journal of the London Mathematical Society, Volume 114, Issue 2, August 2026.Abstract We give a criterion for a collection of polynomials to be a universal Gröbner basis for an ideal in terms of the multidegree of the closure of the corresponding affine variety in (P1)N$(\mathbb {P}^1)^N$. This criterion can be used to give simple proofs of several existing results on universal Gröbner bases.
Daoji Huang, Matt Larson
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High Relative Accuracy Computations With Covariance Matrices of Order Statistics
Mathematical Methods in the Applied Sciences, Volume 49, Issue 11, Page 11794-11810, 30 July 2026.ABSTRACT In many statistical applications, numerical computations with covariance matrices need to be performed. The error made when performing such numerical computations increases with the condition number of the covariance matrix, which is related to the number of variables and the strength of the correlation between the variables. In a recent work,
Juan Baz +3 more
wiley +1 more source
SNMFSMMA: using symmetric nonnegative matrix factorization and Kronecker regularized least squares to predict potential small molecule-microRNA association. [PDF]
RNA Biol, 2020 Zhao Y, Chen X, Yin J, Qu J.
europepmc +1 more source