Monotonicity of the symbolic depth function for edge ideals

Determine whether the symbolic depth function k ↦ depth S/J(G)^{(k)} is non-increasing for every edge ideal J(G) of a finite graph G.

Background

The paper contrasts the behavior of symbolic depth functions for several classes of squarefree monomial ideals. Although the symbolic depth function need not be non-increasing for arbitrary squarefree monomial ideals, and the paper establishes analogous non-monotonicity phenomena for complementary edge ideals, the corresponding question for ordinary edge ideals remains unresolved. Here J(G) denotes the edge ideal of a graph G, and S is the associated polynomial ring.

References

The existence of squarefree monomial ideals whose symbolic depth functions are not non-increasing was shown in [29, 28], while it remains an open problem whether the symbolic depth function of an edge ideal is always non-increasing.

— Regularity, depth and Serre depth of symbolic powers of complementary edge ideals  (2610.23224 - Ficarra et al., 16 Oct 2026) in Section 1, Introduction, p. 4