Full dense-regime realization for every minimum degree

Construct, for every fixed integer d≥2 and every rational number w∈Q∩[d/2,d−1], a finite graph F with minimum degree δ(F)=d and weak saturation limit w_F=w.

Background

The paper proves that, for a prescribed minimum degree d, rational weak saturation limits in the interval [d/2,d−1] can be realized for d≤4 and establishes a substantial subinterval for d≥6. The remaining conjecture asks for the entire interval for every d≥2, including the technically difficult case d=5. The authors specifically mention two possible routes: modifying the subdivision constructions used for d=3 and d=4, or improving expansion bounds for 5-regular graphs.

References

Another problem for future research is to extend the statement of Theorem 1.3 as follows. Conjecture 5.3. For any fixed 8 ≥ 2 and rational w E Qn [8/2, 8 - 1], there exists a graph F with op = 8 and wF = w.

Rational values of the weak saturation limit  (2501.15686 - Ascoli et al., 26 Jan 2025) in Concluding Remarks, Section 5.2, Conjecture 5.3