As of Summer 2002, REPENT or Random Extremists Protecting Endangered Notation & Terminology has been keeping a vigilant eye on those who wantonly use notation and/or terminology in contexts other than that for which they are intended. The announcement of our presence seems to have been respected, until now.
Professor Michael Best is hereby charged with three counts of misuse of Notation.
It seems that Prof. Best, despite his excellent name, has been using Σ to represent a matrix in his C&0 227 course. This symbol is reserved for summation, thank you. To the further confusion of students and befuddlement of notation, Σ-1 has been used to represent the inverse of this matrix.
Furthermore, it seems that "prime-notation" has been used to denote the transpose of a matrix. This symbol is generally accepted to refer to differentiation (even if d/dx is the superior way to denote this). Either complete the notation and turn it into a T or leave it out all together; the students should not be so lazy, or should have enough intelligence to determine the necessary orientation of a matrix to complete the multiplication.
REPENT demands cessation and desistance on these gross misuses of notation. Change the course notes, and change your habits.
You have been warned.
Random Extremists Protecting Endangered
Notation & Terminology
P.S. Reduced sentence and punishment will be granted in this particular case as REPENT believes that the air of the engineering building in which this course is being taught may have been a determining factor.