44th European Cystic Fibrosis Conference, İtalya, 9 - 12 Haziran 2021, cilt.20, ss.43, (Özet Bildiri)
We show that the 14 graphs obtained by $\nabla\mathrm{Y}$ moves on K_7 constitute a complete list of the minor minimal intrinsically knotted graphs on 21 edges. We also present evidence in support of a conjecture that the 20 graph Heawood family, obtained by a combination of $\nabla\mathrm{Y}$ and $\mathrm{Y}\nabla$ moves on K_7, is the list of graphs of size 21 that are minor minimal with respect to the property not 2--apex.