Can symmetric positive definite (SPD) coarse spaces perform well for indefinite Helmholtz problems?

Victorita Dolean, Mark Fry, Matthias Langer. Can symmetric positive definite (SPD) coarse spaces perform well for indefinite Helmholtz problems?. J. Computational Applied Mathematics, 484:117403, 2026. [doi]

@article{DoleanFL26,
  title = {Can symmetric positive definite (SPD) coarse spaces perform well for indefinite Helmholtz problems?},
  author = {Victorita Dolean and Mark Fry and Matthias Langer},
  year = {2026},
  doi = {10.1016/j.cam.2026.117403},
  url = {https://doi.org/10.1016/j.cam.2026.117403},
  researchr = {https://researchr.org/publication/DoleanFL26},
  cites = {0},
  citedby = {0},
  journal = {J. Computational Applied Mathematics},
  volume = {484},
  pages = {117403},
}