@article{KellerLenzSchmidtetal.2019,
  author    = {Keller, Matthias and Lenz, Daniel and Schmidt, Marcel and Schwarz, Michael},
  title     = {Boundary representation of Dirichlet forms on discrete spaces},
  series = {Journal de Math{\´e}matiques Pures et Appliqu{\´e}es},
  volume    = {126},
  journal   = {Journal de Math{\´e}matiques Pures et Appliqu{\´e}es},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0021-7824},
  doi       = {10.1016/j.matpur.2018.10.005},
  pages     = {109 -- 143},
  year      = {2019},
  abstract  = {We describe the set of all Dirichlet forms associated to a given infinite graph in terms of Dirichlet forms on its Royden boundary. Our approach is purely analytical and uses form methods. (C) 2018 Elsevier Masson SAS.},
  language  = {en}
}
@article{KellerSchwarz2020,
  author    = {Keller, Matthias and Schwarz, Michael},
  title     = {Courant's nodal domain theorem for positivity preserving forms},
  series = {Journal of spectral theory},
  volume    = {10},
  journal   = {Journal of spectral theory},
  number    = {1},
  publisher = {EMS Publishing House},
  address   = {Z{\"u}rich},
  issn      = {1664-039X},
  doi       = {10.4171/JST/292},
  pages     = {271 -- 309},
  year      = {2020},
  abstract  = {We introduce a notion of nodal domains for positivity preserving forms. This notion generalizes the classical ones for Laplacians on domains and on graphs. We prove the Courant nodal domain theorem in this generalized setting using purely analytical methods.},
  language  = {en}
}