Reaction systems are discrete dynamical systems that model biochemical processes in living cells using finite sets of reactants, inhibitors, and products. We investigate the computational complexity of a comprehensive set of problems related to the existence of fixed points and attractors in two constrained classes of reaction systems, in which either reactants or inhibitors are disallowed. These problems have biological relevance and have been extensively studied in the unconstrained case; however, they remain unexplored in the context of reactantless or inhibitorless systems. Interestingly, we demonstrate that although the absence of reactants or inhibitors simplifies the system's dynamics, it does not always lead to a reduction in the complexity of the considered problems.

翻译：反应系统是使用有限集合的反应物、抑制剂和产物来模拟活细胞中生化过程的离散动力系统。我们研究了两种受约束反应系统（其中不允许存在反应物或抑制剂）中与不动点和吸引子存在性相关的一系列问题的计算复杂度。这些问题具有生物学意义，并在无约束情形下得到了广泛研究；然而，在无反应物或无抑制剂系统中，它们尚未被探索。有趣的是，我们证明尽管反应物或抑制剂的缺失简化了系统动力学，但并不总是导致所考虑问题的复杂度降低。