To study which are the most general causal structures which are compatible with local quantum mechanics. Oreshkov et al. introduced the notion of a process: a resource shared between some parties that allows for quantum communication between them without a predetermined causal order. These processes can be used to perform several tasks that are impossible in standard quantum mechanics... https://www.bekindtopets.com/limited-stock-Bovi-Shield-Gold-FP-5-L5-HB-best-super/