Effects of interlayer alternation on information diffusion on directed multiplex higher-order networks

In contemporary social networks, information is often transmitted through asynchronous, multi-channel environments where individuals participate in both pairwise and group-based interactions. These processes exhibit strong directionality. For example, interactions may occur from influential users to followers or from dominant voices within group discussions, but most existing contagion models rely on undirected, pairwise interactions and overlook both higher-order structure and directional influence. To address this issue, we propose a SAR (susceptible-adopted-recovered) model for information diffusion on directed multiplex higher-order networks. Each layer incorporates both dyadic and group-level interactions, and diffusion proceeds via interlayer alternation across layers. Directionality is embedded in the higher-order structure via a tunable directionality weight that captures heterogeneous influence among group members. Simulation results reveal a non-monotonic dependence of the final diffusion size on the interlayer alternation probability, with suppression emerging under intermediate alternation regimes. Enhancing directional transmission within higher-order structures can mitigate this suppression and facilitate broader diffusion. Theoretical predictions are consistent with simulation outcomes, validating the proposed framework. Our findings highlight the importance of incorporating directional group interactions and interlayer alternation in models of information diffusion, offering new insights into how structural and temporal heterogeneities jointly regulate information diffusion in multilayer social systems.