Critical-curve conjecture for the generalized deterministic-cure contact process

Determine whether, for every fixed resetting probability p∈[0,1], the generalized contact process with deterministic cures CPDC(λ,p) has a phase transition at a critical infection rate λ_c(p), and whether its critical curve is the weighted harmonic interpolation λ_c(p)=λ_c(0)λ_c(1)/[(1−p)λ_c(1)+pλ_c(0)].

Background

The paper studies CPDC(λ,p) on Zd, in which infected vertices recover exactly one time unit after infection unless an incoming infection attempt is accepted as a reset with probability p. The endpoint p=0 is the non-resetting Contact Process with Deterministic Cure, while p=1 is the fully resetting Contact Process with Restarting Deterministic Cure. Because deterministic recovery deadlines can shield later infection attempts, the process is generally non-attractive for p<1, making standard monotonicity-based phase-transition arguments unavailable.

The paper proves uniform extinction for λ<1/(2d) and, in dimensions d≥2, uniform survival above an oriented-percolation-based bound. It establishes the existence of a phase transition in λ for p=1 using attractiveness, but does not establish the corresponding phase transition for every p∈[0,1] or the proposed interpolation formula. The conjectured numerical values in dimension two are λ_c(0)≈0.40755 and λ_c(1)≈0.33247.

References

Motivated by the numerical results in Figure~\ref{fig:interpolaharm}, we propose the following conjecture for the critical curve.

For any fixed $p\in[0,1]$, there is a phase transition in $\lambda$; that is, there exists a parameter $\lambda_c(p)$ such that the CPDC$(\lambda,p)$ becomes extinct for $\lambda<\lambda_{c}(p)$ and survives with positive probability for $\lambda>\lambda_{c}(p)$. Moreover, the critical curve is given by the weighted harmonic interpolation

\lambda_c(p)

\frac{\lambda_c(0)\lambda_c(1)} {(1-p)\lambda_c(1)+p\lambda_c(0)}.

Numerically, $\lambda_c(0)\approx0.40755$ and $\lambda_c(1)\approx0.33247$ for $\mathbb{Z}{2}$.

— Extinction and Survival for a Generalized Contact Process with Deterministic Cures  (2609.29425 - Garcia et al., 24 Sep 2026) in Introduction, immediately following Corollary; displayed Conjecture