Portaluri, Alessandro; Wu, Li; Yang, Ran A generalized index theory for non-Hamiltonian system. (English) Zbl 1523.58024 J. Differ. Equations 369, 180-214 (2023). Reviewer: Mohsen Timoumi (Monastir) MSC: 58J30 47H11 55M25 58J20 35K57 PDFBibTeX XMLCite \textit{A. Portaluri} et al., J. Differ. Equations 369, 180--214 (2023; Zbl 1523.58024) Full Text: DOI arXiv
Portaluri, Alessandro; Wu, Li; Yang, Ran Linear instability for periodic orbits of non-autonomous Lagrangian systems. (English) Zbl 1456.58013 Nonlinearity 34, No. 1, 237-272 (2021). MSC: 58E10 53C22 53D12 58J30 PDFBibTeX XMLCite \textit{A. Portaluri} et al., Nonlinearity 34, No. 1, 237--272 (2021; Zbl 1456.58013) Full Text: DOI arXiv
Hu, Xijun; Wu, Li; Yang, Ran Morse index theorem of Lagrangian systems and stability of brake orbit. (English) Zbl 1437.37071 J. Dyn. Differ. Equations 32, No. 1, 61-84 (2020). Reviewer: Mircea Crâşmăreanu (Iaşi) MSC: 37J39 37J25 37J46 53D12 PDFBibTeX XMLCite \textit{X. Hu} et al., J. Dyn. Differ. Equations 32, No. 1, 61--84 (2020; Zbl 1437.37071) Full Text: DOI arXiv
Hu, Xijun; Portaluri, Alessandro; Yang, Ran A dihedral Bott-type iteration formula and stability of symmetric periodic orbits. (English) Zbl 1485.70008 Calc. Var. Partial Differ. Equ. 59, No. 2, Paper No. 51, 40 p. (2020). Reviewer: Stefan Suhr (Bochum) MSC: 70F07 37C81 53D12 58J30 PDFBibTeX XMLCite \textit{X. Hu} et al., Calc. Var. Partial Differ. Equ. 59, No. 2, Paper No. 51, 40 p. (2020; Zbl 1485.70008) Full Text: DOI arXiv
Hu, Xijun; Portaluri, Alessandro; Yang, Ran Instability of semi-Riemannian closed geodesics. (English) Zbl 1427.58005 Nonlinearity 32, No. 11, 4281-4316 (2019). MSC: 58E10 53C22 53D12 58J30 PDFBibTeX XMLCite \textit{X. Hu} et al., Nonlinearity 32, No. 11, 4281--4316 (2019; Zbl 1427.58005) Full Text: DOI arXiv