According to Rule 42(1)(c) the description must (at least implicitly) mention the technical problem the application intends to solve (see also F‑II, 4.5). This allows the technical problem underlying the invention to be recognised despite the fact that it might not be immediately apparent from the claims.

However, if the objective technical problem addressed by the claimed invention changes in view of the retrieved prior art (see G‑VII, 5.3, H‑V, 2.4, and T 39/93, OJ EPO 1997, 134), it has to be redefined such that it remains related to the problem initially (explicitly or implicitly) mentioned in the application (see G‑VII, 5.2; see also T 184/82, OJ EPO 1984, 261, and T 732/89).