Special vertices in the Grünbaum–Shephard–Geis catalogue
Determine which irreducible simplicial arrangements in the Grünbaum–Shephard–Geis catalogue of arrangements in real projective three-space admit a special vertex.
References
Question 7.7. Which irreducible simplicial arrangements in the Gr¨unbaum–Shephard–Geis catalogue [5, 4] admit a special vertex ?
— Simplicial arrangements in real projective three-space revisited
(2608.28254 - Janasz et al., 28 Aug 2026) in Question 7.7, end of Section 7