User talk:MWinter4/4-flat graphs

Future work
MWinter4 (talk) 20:22, 28 May 2024 (UTC)
 * 4-flat graphs are closed under cloning edges and $$\Delta\mathrm{Y}$$-transformations. It is conjectured that they are also closed under $$\mathrm{Y}\Delta$$-transformations.
 * Alternative to the notion of 4-flat graphs based on almost embeddings ($$\mathcal I_4$$) with its higher-dimensional analogues ($$\mathcal I_d$$) and leading to van der Holst's topological graph invariant $$\sigma$$.
 * Alternative definitions of 4-flat using general CW-complex (instead of regular CW-complexes).