Solution suggestion Oblig 2

I've corrected the hand-ins of Oblig 2, and I'm happy to say that the performance was broadly very good. A solution suggestion to Oblig 2 is uploaded to the "file" directory in Canvas.  

Particularly in question 3 a) it was perhaps not clear whether a simple reference to the theory or a mathematical argument for the sought maximum principle was requested. Let me therefore note that for full score on an exam, I expect a mathematical argument for why a property holds, unless otherwise is clearly stated.