“…The existence of solutions to and their regularity has been studied in, for example, (variational solution). We summarise some known results in the following theorem and we also refer to the discussion preceding and after [, Proposition 3.1] for more details. To briefly describe the notion of a variational solution we consider the mapping defined by A continuous, H ‐valued, ‐adapted process is called a variational solution of , if for its equivalence class we have , for some , and Theorem If …”