Considering an almost Ricci soliton (ARS) $ \left(N, g, \eta, \kappa \right) $ on a compact Riemannian manifold $ (N, g) $, we use the Ricci curvature in the direction of the potential vector field $ \eta $ to derive necessary and sufficient conditions for $ (N, g) $ to be isometric to a sphere. This expands on several recent results regarding Ricci solitons and almost Ricci solitons by applying specific integral inequalities involving the Ricci curvature evaluated in the direction $ \eta $. Furthermore, we present conditions under which $ \eta $ is either Killing or parallel; in particular, the ARS is trivial.
Citation: Mohammed Guediri, Norah Alshehri. Rigidity of almost Ricci solitons on compact Riemannian manifolds[J]. AIMS Mathematics, 2025, 10(6): 13524-13539. doi: 10.3934/math.2025608
Considering an almost Ricci soliton (ARS) $ \left(N, g, \eta, \kappa \right) $ on a compact Riemannian manifold $ (N, g) $, we use the Ricci curvature in the direction of the potential vector field $ \eta $ to derive necessary and sufficient conditions for $ (N, g) $ to be isometric to a sphere. This expands on several recent results regarding Ricci solitons and almost Ricci solitons by applying specific integral inequalities involving the Ricci curvature evaluated in the direction $ \eta $. Furthermore, we present conditions under which $ \eta $ is either Killing or parallel; in particular, the ARS is trivial.
| [1] |
R. S. Hamilton, Three manifolds with positive Ricci curvature, J. Differ. Geom., 17 (1982), 255–306. https://doi.org/10.4310/jdg/1214436922 doi: 10.4310/jdg/1214436922
|
| [2] |
S. Pigola, Ricci almost solitons, Ann. Scuola Norm. Sup. Pisa Cl. Sci., 5 (2011), 757–799. https://doi.org/10.2422/2036-2145.2011.4.01 doi: 10.2422/2036-2145.2011.4.01
|
| [3] |
A. Barros, E Jr. Ribeiro, Some characterizations for compact almost Ricci solitons, Proc. Amer. Math. Soc., 140 (2012), 1033–1040. https://doi.org/10.1090/S0002-9939-2011-11029-3 doi: 10.1090/S0002-9939-2011-11029-3
|
| [4] |
A. Barros, R. Batista, R. E. Jr. Ribeiro, Compact almost Ricci solitons with constant scalar curvature are gradient, Monatsh. Math., 174 (2014), 29–39. https://doi.org/10.48550/arXiv.1209.2720 doi: 10.48550/arXiv.1209.2720
|
| [5] | G. Perelman, The entropy formula for the Ricci flow and its geometric applications, Preprint, 2002. https://doi.org/10.48550/arXiv.math/0211159 |
| [6] |
R. S. Hamilton, The Ricci flow on surfaces, Contemp. Math., 71 (1988), 237–261. https://doi.org/10.1090/conm/071/954419 doi: 10.1090/conm/071/954419
|
| [7] |
A. Barros, R. Batista, E. Jr. Ribeiro, Rigidity of gradient almost Ricci solitons, Illinois J. Math., 56 (2012), 1267–1279. https://doi.org/10.1215/ijm/1399395831 doi: 10.1215/ijm/1399395831
|
| [8] |
G. Maschler, Almost soliton duality, Adv. Geom., 15 (2015), 159–166. https://doi.org/10.48550/arXiv.1301.0290 doi: 10.48550/arXiv.1301.0290
|
| [9] |
R. Sharma, Almost Ricci solitons and K-contact geometry, Monatsh. Math., 175 (2014), 621–628. https://doi.org/10.1007/s00605-014-0657-8 doi: 10.1007/s00605-014-0657-8
|
| [10] | A. Brasil, E. Costa, E. Jr. Ribeiro, Hitchin–Thorpe inequality and Kaehler metrics for compact almost Ricci soliton, Ann. Mat. Pura Appl., 4 (2014), 1851–1860. Available from: arXiv.org/pdf/2203.14916 |
| [11] |
T. Nagano, K. Yano, Einstein spaces admitting a one-parameter group of conformal transformations, Ann. Math., 69 (1959), 451–461. https://doi.org/10.2307/1970193 doi: 10.2307/1970193
|
| [12] |
F. E. S. Feitosa, A. A. Freitas Filho, J. N. V. Gomes, R. S. Pina, Gradient Ricci almost soliton warped product, J. Geom. Phys., 143 (2019), 22–32. https://doi.org/10.48550/arXiv.1507.03038 doi: 10.48550/arXiv.1507.03038
|
| [13] |
A. M. Blaga, B. Y. Chen, On conformal collineation and almost Ricci solitons, J. Geom. Phys., 207 (2025), 105354. https://doi.org/10.48550/arXiv.2210.05284 doi: 10.48550/arXiv.2210.05284
|
| [14] |
P. D. Weidman, L. G. Redekopp, Initial conditions and korteweg-de vries solitons, J. Eng. Mech. Div., 108 (1982), 277–289. https://doi.org/10.1061/JMCEA3.0002811 doi: 10.1061/JMCEA3.0002811
|
| [15] | S. Wang, Novel soliton solutions of CNLSEs with hirota bilinear method, J. Opt. 52 (2023), 1602–1607. https://doi.org/10.1007/s12596-022-01065-x |
| [16] |
P. Petersen, P. W. Wylie, Rigidity of gradient Ricci solitons, Pacific J. Math., 241 (2009), 329–345. https://doi.org/10.48550/arXiv.0710.3174 doi: 10.48550/arXiv.0710.3174
|
| [17] | B. O'Neill, Semi-Riemannian Geometry with Applications to Relativity, San Diego, USA, : Aca-demic Press, 1983. |
| [18] | K. Yano, Integral Formulas in Riemannian Geometry, Marcel Dekker, NY, 1970. https://doi.org/10.1017/S0008439500031520 |
| [19] | S. Deshmukh, H. Al-Sodais, A note on almost Ricci solitons, Anal. Math. Phys. 10 (2020). https://doi.org/10.3390/sym12020289 |
| [20] | N. Alshehri, M. Guediri, Characterizing affine vector fields on pseudo-Riemannian manifolds, Axioms, 13 (2024). https://doi.org/10.3390/axioms13120835 |
| [21] | W. A. Poor, Differential geometric structures, Dover Publications, (2015). |