“…Extending the concept of lower-upper (in short, LU) optimal solution in Wu (2008), and as well as in Jayswal et al (2011), we may receive the notion of lower-upper optimal solution to the interval-valued optimization problems with constraints, even in any vector optimization problem with equilibrium constraints. Based on the fact that the class of interval-valued nonlinear programming problems has been extensively studied on optimality and duality by many researchers in recent years, e.g., in Bhurjee and Panda (2015), Bhurjee and Panda (2016), Bot and Grad (2010), Jayswal et al (2011), Jayswal et al (2016), Luu and Mai (2018), More (1983), Wu (2008) and the construction of Wolfe and Mond-Weir dual models to these has not been established yet, we continue to study and develop these result on optimality and duality to the interval-valued optimization problem with equilibrium constraints and an application of the obtained results for these dual models will be presented in the literature.…”