2026/07/21 by Suyoung Choi, Yuanxin Guan, Hyeontae Jang +1
#math.AT #math.CO
We study the lifting problem for mod 2 characteristic maps over simplicial 3-spheres. Using a bad-block partition of the universal complex X(ℤ24), we prove an avoidance criterion for liftability. We show that every simplicial 3-sphere with at most 20 vertices has the toric lifting property. We also obtain image-size and join-type results, and prove sharpness of the image-size bound in the universal-complex sense.