In ubiquitous environments a vast amount of mobile human and software entities, each with limited resources and knowledge, needs to interact with each other to achieve common and/or individual goals within a specific context. Due to their autonomy, proactiveness, mobility, social capability, and the successful implementation of agent mediated applications and services over the Web, different scenarios have been proposed in literature for the use of agents in ubiquitous environments for a wide range of applications such as user interfaces, mobile computing, information retrieval and filtering, smart messaging, telecommunication and m-commerce. In this paper, we address the problem of modeling agents' interaction in ubiquitous environments. We argue agents' interactions can be modeled using norms, which are represented mathematically as zero set of n-variate functions. We utilize the barycentic coordinates to show how agents should behave based on established protocols, rules of conduct or accepted social practices.