In this paper, by using the Saloff-Coste Sobolev-type inequality and Nash-Moser iteration, we proved a local gradient estimate of Cheng-Yau type for positive solutions to the equation
$ \Delta_f v^{\tau}+\lambda(x)v^l = 0 $
on metric measure spaces with $ m $-Bakry-Emery Ricci curvature bounded from below. Here $ \tau > 0 $ and $ l $ were constants, and $ \lambda(x) $ was allowed to change sign. As applications, we also obtained a Liouville-type result and Harnack's inequality. Compared with previous works, this paper did not need to suppose the positive solutions are bounded and extended the ranges of $ \tau $ and $ l $.
Citation: Fanqi Zeng, Cheng Jin, Peilong Dong, Xinying Jiang. Cheng-Yau type gradient estimates for $ \Delta_f v^{\tau}+\lambda(x)v^l = 0 $ on smooth metric measure spaces[J]. Electronic Research Archive, 2025, 33(7): 4307-4326. doi: 10.3934/era.2025195
In this paper, by using the Saloff-Coste Sobolev-type inequality and Nash-Moser iteration, we proved a local gradient estimate of Cheng-Yau type for positive solutions to the equation
$ \Delta_f v^{\tau}+\lambda(x)v^l = 0 $
on metric measure spaces with $ m $-Bakry-Emery Ricci curvature bounded from below. Here $ \tau > 0 $ and $ l $ were constants, and $ \lambda(x) $ was allowed to change sign. As applications, we also obtained a Liouville-type result and Harnack's inequality. Compared with previous works, this paper did not need to suppose the positive solutions are bounded and extended the ranges of $ \tau $ and $ l $.
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