https://science.thanglong.edu.vn/index.php/volc/issue/feedThang Long Journal of Science: Mathematics and Mathematical Sciences2025-05-30T00:00:00+00:00Thang Long Journal of Science: Mathematics and Mathematical Sciencestapchikh@thanglong.edu.vnOpen Journal Systems<p>About Mathematics and Mathematical Sciences (Vol. C), published in English language.</p>https://science.thanglong.edu.vn/index.php/volc/article/view/219On invariants of plane curve singularities in positive characteristic2025-01-06T02:45:30+00:00Hong Duc Nguyenduc.nh@thanglong.edu.vnIn this survey paper we give an overview on some aspects of singularities of algebraic plane curves over an algebraically closed field of arbitrary characteristic. We review, in particular, classical results and recent developments on invariants of plane curve singularities.2025-03-12T00:00:00+00:00Copyright (c) 2025 Thang Long Journal of Science: Mathematics and Mathematical Scienceshttps://science.thanglong.edu.vn/index.php/volc/article/view/222On meromorphic solution of linear difference-differential equation via partially shared values of meromorphic functions and its growth2025-02-13T08:53:08+00:00Thin Van Nguyenthinmath@gmail.comAssoc Phương Hà Trầnphuonght@tnue.edu.vnIn this paper, we investigate shared value problems related to a meromorphic function of hyper order less than one and its linear differencedifferential polynomial. In general, under certain conditions of sharing values of the meromorphic functions and their difference-differential polynomial, a given meromorphic function must satisfy a difference-differential equation. Furthermore, we also study the order of meromorphic solutions of some classes of difference-differential equations.2025-03-02T00:00:00+00:00Copyright (c) 2025 Thang Long Journal of Science: Mathematics and Mathematical Scienceshttps://science.thanglong.edu.vn/index.php/volc/article/view/227An algorithm for solving the variational inequality problem over the solution set of the split variational inequality and fixed point problem2025-03-18T03:13:21+00:00Việt Anh Trầntranvietanh@outlook.comIn this paper, we introduce a new algorithm for solving strongly monotone variational inequality problem, where the constraint set is the solution set of the split variational inequality and fixed point problem. Our method uses dynamic step sizes selected based on information of the previous step, which gives strong convergence result without the prior knowledge of the given bounded linear operator’s norm. In addition, using our method, we do not require any information of the Lipschitz and strongly monotone constants of the mappings. Several corollaries of our main result are also presented. Finally, a numerical example has been given to illustrate the effectiveness of our proposed algorithm.2025-04-02T00:00:00+00:00Copyright (c) 2025 Thang Long Journal of Science: Mathematics and Mathematical Scienceshttps://science.thanglong.edu.vn/index.php/volc/article/view/231Random dynamical system generated by nonautonomous stochastic differential equations driven by fractional Brownian motions2025-05-26T01:44:00+00:00Doctor Hong Phan Thanhhongpt@thanglong.edu.vnIn this paper, we prove that a non-autonomous stochastic differential equation generates a continuous random dynamical system. The flow then possesses a random pullback attractor under thedissipativity condition(s) of the drift and smallness of diffusion part.2025-05-25T00:00:00+00:00Copyright (c) 2025 Thang Long Journal of Science: Mathematics and Mathematical Scienceshttps://science.thanglong.edu.vn/index.php/volc/article/view/235Images of the Singer transfers and their possibility to be injective2025-05-12T02:50:28+00:00Prof Huu Viet Hung Nguyennhvhung@gmail.comThis article is an attempt to investigate the possibility to be injective of the Singer transfer TrM s : F2 ⊗GLs P(H∗Vs ⊗ M∗) → Exts A (Σ-sM, F2) for M being the A -modules F2 = Hå∗S0 or Hå∗RP∞. The existence of a positive stem critical element of Exts,t A (Hå∗RP∞, F2) in the image of the transfer TrRP∞ s is equivalent to the existence of a positive stem critical element of Exts+1,t+1 A (F2, F2) in the image of the transfer Trs+1. If the existences happen, then TrRP∞ s and Trs+1 are not injective. We show that the critical element P h ä2 is not in the image of the fourth transfer, TrRP∞ 4 : F2 ⊗GL4 P(H∗V4 ⊗ Hå∗RP∞)t-4 → Ext4 A,t(Hå∗RP∞, F2). Singer’s conjecture is still open, as we have not known any critical element, which is in the image of the transfer.2025-05-12T00:00:00+00:00Copyright (c) 2025 https://science.thanglong.edu.vn/index.php/volc/article/view/228Balancing Accuracy and Interpretability in Credit Risk Modeling: Evidence from Peer-to-Peer Lending2025-04-15T01:26:53+00:00Thuy Tien Dinhdinhthuytien@thanglong.edu.vnThi Tra My Nguyenmyntt@thanglong.edu.vnAccurate credit risk assessment is crucial for the stability and growth of peer-to-peer (P2P) lending platforms. This study investigates the effectiveness of machine learning models in predicting loan defaults using historical Lending Club data. We evaluate logistic regression, decision tree, and random forest, employing feature engineering techniques like one-hot and weight of evidence encoding. Model performance is assessed using K-fold cross-validation and metrics such as accuracy and AUC. To enhance model interpretability, we utilize explainable AI techniques like LIME and SHAP, enabling lenders and borrowers to understand the factors driving loan defaults. Our findings demonstrate that while complex models offer higher predictive accuracy, simpler models like logistic regression with WoE encoding provide a suitable balance between accuracy and interpretability, fostering trust and responsible lending within the P2P lending ecosystem.Copyright (c) 2025 Thang Long Journal of Science: Mathematics and Mathematical Sciences