## Schedule

**Wednesday, September 30**: Checkup 2 revisions (if desired), due at the beginning of class or end of office hours today.

**Friday, October 9**: Problem Set 2 (moved from original deadline of
October 2). Problem Set 2 will be posted by tomorrow.

**Monday, October 19**: Midterm Exam

No classes Monday, October 5!

# Notes

If we have 20% of the network hashing power, calculate the proportion of blocks we will win if we mine selfishly. Do we come out ahead or behind?

Why does our formular for E not work for alpha greater than a half?

Compute the constant on slide 29, “Expected share reward”. You may have to look up the Taylor’s expansion series for natural logarithm.

Does mining in a pool increase your reward or decrease it? Explain.

If a pool is paying out proportionally, and you are profiting by pool hopping in and out of it, is somebody else making a loss? Who and how?