@article{KemptonMuenchYau2021,
  author    = {Kempton, Mark and M{\"u}nch, Florentin and Yau, Shing-Tung},
  title     = {A homology vanishing theorem for graphs with positive curvature},
  series = {Communications in analysis and geometry},
  volume    = {29},
  journal   = {Communications in analysis and geometry},
  number    = {6},
  publisher = {International Press of Boston},
  address   = {Somerville},
  issn      = {1019-8385},
  doi       = {10.4310/CAG.2021.v29.n6.a5},
  pages     = {1449 -- 1473},
  year      = {2021},
  abstract  = {We prove a homology vanishing theorem for graphs with positive Bakry-' Emery curvature, analogous to a classic result of Bochner on manifolds [3]. Specifically, we prove that if a graph has positive curvature at every vertex, then its first homology group is trivial, where the notion of homology that we use for graphs is the path homology developed by Grigor'yan, Lin, Muranov, and Yau [11]. We moreover prove that the fundamental group is finite for graphs with positive Bakry-' Emery curvature, analogous to a classic result of Myers on manifolds [22]. The proofs draw on several separate areas of graph theory, including graph coverings, gain graphs, and cycle spaces, in addition to the Bakry-Emery curvature, path homology, and graph homotopy. The main results follow as a consequence of several different relationships developed among these different areas. Specifically, we show that a graph with positive curvature cannot have a non-trivial infinite cover preserving 3-cycles and 4-cycles, and give a combinatorial interpretation of the first path homology in terms of the cycle space of a graph. Furthermore, we relate gain graphs to graph homotopy and the fundamental group developed by Grigor'yan, Lin, Muranov, and Yau [12], and obtain an alternative proof of their result that the abelianization of the fundamental group of a graph is isomorphic to the first path homology over the integers.},
  language  = {en}
}
@article{KellerMuench2019,
  author    = {Keller, Matthias and M{\"u}nch, Florentin},
  title     = {A new discrete Hopf-Rinow theorem},
  series = {Discrete Mathematics},
  volume    = {342},
  journal   = {Discrete Mathematics},
  number    = {9},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0012-365X},
  doi       = {10.1016/j.disc.2019.03.014},
  pages     = {2751 -- 2757},
  year      = {2019},
  abstract  = {We prove a version of the Hopf-Rinow theorem with respect to path metrics on discrete spaces. The novel aspect is that we do not a priori assume local finiteness but isolate a local finiteness type condition, called essentially locally finite, that is indeed necessary. As a side product we identify the maximal weight, called the geodesic weight, generating the path metric in the situation when the space is complete with respect to any of the equivalent notions of completeness proven in the Hopf-Rinow theorem. As an application we characterize the graphs for which the resistance metric is a path metric induced by the graph structure.},
  language  = {en}
}
@article{LiuMuenchPeyerimhoff2018,
  author    = {Liu, Shiping and M{\"u}nch, Florentin and Peyerimhoff, Norbert},
  title     = {Bakry-Emery curvature and diameter bounds on graphs},
  series = {Calculus of variations and partial differential equations},
  volume    = {57},
  journal   = {Calculus of variations and partial differential equations},
  number    = {2},
  publisher = {Springer},
  address   = {Heidelberg},
  issn      = {0944-2669},
  doi       = {10.1007/s00526-018-1334-x},
  pages     = {9},
  year      = {2018},
  abstract  = {We prove finiteness and diameter bounds for graphs having a positive Ricci-curvature bound in the Bakry-{\´E}mery sense. Our first result using only curvature and maximal vertex degree is sharp in the case of hypercubes. The second result depends on an additional dimension bound, but is independent of the vertex degree. In particular, the second result is the first Bonnet-Myers type theorem for unbounded graph Laplacians. Moreover, our results improve diameter bounds from Fathi and Shu (Bernoulli 24(1):672-698, 2018) and Horn et al. (J f{\"u}r die reine und angewandte Mathematik (Crelle's J), 2017, https://doi.org/10.1515/crelle-2017-0038) and solve a conjecture from Cushing et al. (Bakry-{\´E}mery curvature functions of graphs, 2016).},
  language  = {en}
}
@phdthesis{Muench2019,
  author    = {M{\"u}nch, Florentin},
  title     = {Discrete Ricci curvature, diameter bounds and rigidity},
  school      = {Universit{\"a}t Potsdam},
  pages     = {68},
  year      = {2019},
  language  = {en}
}
@article{KellerMuenchPogorzelski2016,
  author    = {Keller, Matthias and M{\"u}nch, Florentin and Pogorzelski, Felix},
  title     = {Geometry and spectrum of rapidly branching graphs},
  series = {Mathematische Nachrichten},
  volume    = {289},
  journal   = {Mathematische Nachrichten},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {0025-584X},
  doi       = {10.1002/mana.201400349},
  pages     = {1636 -- 1647},
  year      = {2016},
  abstract  = {We study graphs whose vertex degree tends to infinity and which are, therefore, called rapidly branching. We prove spectral estimates, discreteness of spectrum, first order eigenvalue and Weyl asymptotics solely in terms of the vertex degree growth. The underlying techniques are estimates on the isoperimetric constant. Furthermore, we give lower volume growth bounds and we provide a new criterion for stochastic incompleteness. (C) 2016 WILEY-VCH Verlag GmbH \& Co. KGaA, Weinheim},
  language  = {en}
}
@article{KellerLenzMuenchetal.2016,
  author    = {Keller, Matthias and Lenz, Daniel and M{\"u}nch, Florentin and Schmidt, Marcel and Telcs, Andras},
  title     = {Note on short-time behavior of semigroups associated to self-adjoint operators},
  series = {Bulletin of the London Mathematical Society},
  volume    = {48},
  journal   = {Bulletin of the London Mathematical Society},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0024-6093},
  doi       = {10.1112/blms/bdw054},
  pages     = {935 -- 944},
  year      = {2016},
  abstract  = {We present a simple observation showing that the heat kernel on a locally finite graph behaves for short times t roughly like t(d), where d is the combinatorial distance. This is very different from the classical Varadhan-type behavior on manifolds. Moreover, this also gives that short-time behavior and global behavior of the heat kernel are governed by two different metrics whenever the degree of the graph is not uniformly bounded.},
  language  = {en}
}
@article{BourneCushingLiuetal.2018,
  author    = {Bourne, D. P. and Cushing, D. and Liu, S. and M{\"u}nch, Florentin and Peyerimhoff, Norbert},
  title     = {Ollivier-Ricci idleness functions of graphs},
  series = {SIAM Journal on Discrete Mathematics},
  volume    = {32},
  journal   = {SIAM Journal on Discrete Mathematics},
  number    = {2},
  publisher = {Society for Industrial and Applied Mathematics},
  address   = {Philadelphia},
  issn      = {0895-4801},
  doi       = {10.1137/17M1134469},
  pages     = {1408 -- 1424},
  year      = {2018},
  abstract  = {We study the Ollivier-Ricci curvature of graphs as a function of the chosen idleness. We show that this idleness function is concave and piecewise linear with at most three linear parts, and at most two linear parts in the case of a regular graph. We then apply our result to show that the idleness function of the Cartesian product of two regular graphs is completely determined by the idleness functions of the factors.},
  language  = {en}
}
@article{Muench2017,
  author    = {M{\"u}nch, Florentin},
  title     = {Remarks on curvature dimension conditions on graphs},
  series = {Calculus of variations and partial differential equations},
  volume    = {56},
  journal   = {Calculus of variations and partial differential equations},
  publisher = {Springer},
  address   = {Heidelberg},
  issn      = {0944-2669},
  doi       = {10.1007/s00526-016-1104-6},
  pages     = {8},
  year      = {2017},
  abstract  = {We show a connection between the CDE′ inequality introduced in Horn et al. (Volume doubling, Poincar{\´e} inequality and Gaussian heat kernel estimate for nonnegative curvature graphs. arXiv:1411.5087v2, 2014) and the CDψ inequality established in M{\"u}nch (Li-Yau inequality on finite graphs via non-linear curvature dimension conditions. arXiv:1412.3340v1, 2014). In particular, we introduce a CDφψ inequality as a slight generalization of CDψ which turns out to be equivalent to CDE′ with appropriate choices of φ and ψ. We use this to prove that the CDE′ inequality implies the classical CD inequality on graphs, and that the CDE′ inequality with curvature bound zero holds on Ricci-flat graphs.},
  language  = {en}
}