This levels appears to be very difficult. I think part of the problem is that students start the planet one week and then try to finish it the next week. By that time, they’ve forgotten all lemmas that they already proved, and get stuck at places like:
I have added more explanations to levels 8 and 9, and partially rewritten level 9: 5c175781ba6a91ad0c3e2cc074b150ce43d0928d, bed81540be524ee91e5b34950543faaa4609ba7d
This levels appears to be very difficult. I think part of the problem is that students start the planet one week and then try to finish it the next week. By that time, they’ve forgotten all lemmas that they already proved, and get stuck at places like:
https://github.com/hhu-adam/Robo/blob/20750845be33e8e6f91b3811d264202ee0cc7b91/Game/Levels/MatrixTrace/L09_EvalOnEBasis.lean#L83
And I also don’t know how to proceed because I don’t know all lemmas that have already been proved off the top of my head.