Classifying Fano Complexity-One $T$-Varieties via Divisorial Polytopes

The correspondence between Gorenstein Fano toric varieties and reflexive polytopes has been generalized by Ilten and S"u{\ss} to a correspondence between Gorenstein Fano complexity-one $T$-varieties and Fano divisorial polytopes. Motivated by the finiteness of reflexive polytopes in fixed dimension, we show that over a fixed base polytope, there are only finitely many Fano divisorial polytopes, up to equivalence. We classify two-dimensional Fano divisorial polytopes, recovering Huggenberger’s classification of Gorenstein del Pezzo ${\mathbb{K}}^{\ast }$-surfaces. Furthermore, we show that any three-dimensional Fano divisorial polytope is equivalent to one involving only eight functions.