We found an error in the equation describing the covariance in half-sibs as I was lecturing on Thursday. I just verified that the error is also in the accompanying notes – not surprising since the lecture slides are directly extracted from the lecture notes. I’ve now corrected the notes and uploaded new versions. You can find them either from the Lecture Detail page or from the links below. The correction will also appear in the book version of the notes that I’ll compile at the end of the semester.