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時間：4月21日中午12點-14點

地點：明德主樓729會議室

報告人：魏杰

講座題目：Does Principal Component Analysis Preserve the Sparsity in Sparse Weak Factor Models?

研討會摘要：

This paper studies the principal component (PC) method-based estimation of weak factor models with sparse loadings. We uncover an intrinsic near-sparsity preservation property for the PC estimators of loadings, which comes from the approximately upper triangular (block) structure of the rotation matrix. It implies an asymmetric relationship among factors: the rotated loadings for a stronger factor can be contaminated by those from a weaker one, but the loadings for a weaker factor is almost free of the impact of those from a stronger one. More importantly, the fnding implies that there is no need to use complicated penalties to sparsify the loading estimators. Instead, we adopt a simple screening method to recover the sparsity and construct estimators for various factor strengths. In addition, for sparse weak factor models, we provide a singular value thresholding-based approach to determine the number of factors and establish uniform convergence rates for PC estimators, which complement Bai and Ng (2023). The accuracy and efciency of the proposed estimators are investigated via Monte Carlo simulations. The application to the FRED-QD dataset reveals the underlying factor strengths and loading sparsity as well as their dynamic features.

主講人介紹：

魏杰，華中科技大學經濟學院副教授，美國加州大學河濱分校經濟學博士。研究興趣為面板和因子模型、半參數非參數回歸和實證資產定價。論文發表于Oxford Bulletin of Economics and Statistics、Energy Economics和Economics Letters等期刊，主持國家自然科學青年基金和教育部人文社科青年基金項目。