Surprisingly excellent ..great storyline and acting

Saw this last night and was blown over. I love murder mysteries but this was even more than that. The math teacher and the mother were especially well-acted characters. I don't want to give spoilers but I felt that the mother/daughter actions were not unjust but were self-defense. But I guess that idea wouldn't fly in a criminal court. It was interesting to see how the smart well-meaning physicist , in trying to do good by cracking math genius's scheme, actually made everybody's lives worse than they should be in my estimation anyway. The scenes of the math wizard and the physicist together on a the snowy mountain climb on the Japanese Alps, each suspicious of the other, were fabulous. The ending, which revealed secrets held back from the viewer, did serve to explain how and why the math genius planned it all. However I lost sympathy for him. I wanted him to be a type of hero. I think the movie would have been better if the writer had figured out a decent way to deal with the dead body issue. In fact it seemed like that if the dead body had simply disappeared forever all would have been well enough. Actually I'm not sure why the police could strongly suspect, without physical clues, a meek petite mother of doing a brutal murder like that anyway. Even with that, I still thought that the movie was well-made.