Inspired by this question, I thought of something more. As Tim says, and I ageree, one more often sees repeated use of "Hence", "Therefore" etc. in a mathematical proof, and not very often do people ...
It seems to me that "so" is seldom used in math proofs. Instead, "hence" and "therefore" are used very often, even repeatedly appearing in several sentences in a row. So I wonder if my feeling is ...
In mathematics, "A or B" includes "A and B". Does "either" mean "A or B but not (A and B)" or does it include the possibility of "A and B"? The context might be mathematics, formal logic or ordinary ...