Our main result is a real-time, purely functional (and hence confluently persistent) implementation of deques with catenation.
Indeed, Kosaraju  states, "These ideas might be helpful in making mindeques confluently persistent.
In work independent of ours, Okasaki [1996; 1998] has devised a confluently persistent implementation of catenable stacks (or steques).
Confluently persistant deques via data structural bootstrapping.
Simple confluently persistent catenable lists (extended abstract).