Convex functions on Carnot groups. (English) Zbl 1124.49024
Summary: We consider the definition and regularity properties of convex functions in Carnot groups. We show that various notions of convexity in the subelliptic setting that have appeared in the literature are equivalent. Our point of view is based on thinking of convex functions as subsolutions of homogeneous elliptic equations.
MSC:
| 49L25 | Viscosity solutions to Hamilton-Jacobi equations in optimal control and differential games |
| 35J70 | Degenerate elliptic equations |
| 35J67 | Boundary values of solutions to elliptic equations and elliptic systems |
| 22E30 | Analysis on real and complex Lie groups |
| 49N60 | Regularity of solutions in optimal control |
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