Abstract
We study Busemann functions, semi-infinite geodesics, and competition interfaces in the exactly solvable last-passage percolation with inhomogeneous exponential weights. New phenomena concerning geodesics arise due to inhomogeneity. These include novel Busemann functions associated with flat regions of the limit shape and thin rectangles, semi-infinite geodesics with intervals of asymptotic directions, non-trivial axis-directed geodesics, intervals with no geodesic directions, and isolated geodesic directions. We further observe a new dichotomy for competition interfaces and second-class customers in a series of memoryless continuous-time queues with inhomogeneous service rates: a second-class customer either becomes trapped or proceeds through the service stations at strictly positive speed.
| Original language | English |
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| Article number | 316 |
| Number of pages | 65 |
| Journal | Communications in Mathematical Physics |
| Volume | 406 |
| Issue number | 12 |
| Early online date | 20 Nov 2025 |
| DOIs | |
| Publication status | Published - 1 Dec 2025 |