Editorial Geometric and Polynomial Approaches of Complex Systems and Control in Mathematics and Applied Sciences Baltazar Aguirre-Hern´ andez , 1 Jorge-Antonio L´ opez-Renter´ ıa , 2 Alejandro Armando Hossian, 3 and Cutberto Romero-Mel´ endez 1 1 Universidad Aut´ onoma Metropolitana, Mexico City, Mexico 2 CONACYT, TecNM, Instituto Tecnol´ ogico de Tijuana, B.C., Tijuana, Mexico 3 Universidad Tecnol´ ogica Nacional, Neuqu´ en, Argentina Correspondence should be addressed to Baltazar Aguirre-Hern´ andez; bahe@xanum.uam.mx Received 27 February 2020; Accepted 27 February 2020; Published 14 May 2020 Copyright © 2020 Baltazar Aguirre-Hern´ andez et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Complex dynamical systems are present in many theoretical and practical domains of the science and engineering: physical processes, man-made systems, deterministic and stochastic control systems, distributed systems, and net- works of leader-follower multiagent systems, between others. e matrix approach of state space has long been the way to address many of the central problems of systems with control. In recent decades, novel methods and approaches for the study of systems, linear and nonlinear, with control are based on a geometrical approach whose objective is to reveal the properties of the geometric skeleton of the dy- namic system. e geometric approach can convert a dif- ficult nonlinear problem into a straight-forward linear one. Geometric control theory and sub-Riemannian geom- etry are areas that play a very important role in complex dynamical systems, searching controllability, optimality, and stability for linear and nonlinear control systems, applying Lie theory techniques, Pontryagin maximum principle, and other geometric and algebraic techniques for robotic con- trol, motion planning problems, complexity on path plan- ning, neurobiological visual processing models, and digital image reconstruction. On the contrary, the use of polynomial theory has been a useful tool to explain the classical and complex behavior of the solutions for a dynamical system, and it is largely exploited in fundamental problems such as controllability, stability, robustness, and other interesting applications in uncertain systems, nonlinear systems, time-delay systems, hybrid systems, and model predictive control. In the paper “Poinacar´ e Map Approach to Global Dy- namics of the Integrated Pest Management Prey-Predator Model,” Zhenzhen Shi et al. studied, by means Poinacar´ e maps, the existence of periodic solutions of an integrated pest management prey-predator model with ratio-depen- dent and impulsive feedback control. e existence and stability of boundary order-one periodic solution is proved, and the authors give conditions for the existence and global stability of order r - 1 periodic solution and for the existence of order k periodic solution. e paper “Availability Equivalence Analysis of a Re- pairable Bridge Network System,” by Jaafar Alghazo et al., discusses availability equivalence factors of a repairable bridge network system where all components have constant failure and repair rates. e authors derive the availability of the original system and improved systems. Two types of availability equivalence factors of the system are obtained in order to compare different system designs. Numerical ex- amples are included for illustrating the obtained results. e proposed models and analysis method are very useful in system engineering. In the paper “On the Delay Interval in Which the Control Delay Systems are Stabilizable,” Jiang Wei studies the stability of single delay systems and uses two-variable polynomials to derive some stability criteria. Besides, he uses these results to compute an interval for the delay where a Hindawi Complexity Volume 2020, Article ID 6281613, 2 pages https://doi.org/10.1155/2020/6281613