Today we’ll make a reduction to prove the Steiner Tree Problem is NP-hard (and therefore NP-complete, since it’s in NP). We won’t prove the reduction correct quite yet, however.

Note: this is a doozy of a reduction. So, it’s good practice for us, but **much** harder than, e.g., the SAT/ELEC problem on the assignment!

- Here is the new handout on NP-hardness of SP.
- For Wednesday, please read section 8.7 of the textbook (about the famous 3-coloring problem in graphs!). This is also a good time to go back and re-skim 8.10. You’ve seen a lot of those problems now!
- No quiz for Wednesday.
- Keep trucking on the assignment due Thursday!