Professor Septima Vector (fl. 1974—1996) was a witch and Professor of Arithmancy at Hogwarts School of Witchcraft and Wizardry from at least the 1991–1992 school year. She may have also been the Advanced Arithmancy Studies teacher. Professor Vector was known among students as a "really strict" teacher, so much so that some pupils were unsure whether to take her classes. She was also known for giving her pupils plenty of complicated homework. Her subject was Hermione Granger's favourite subject while she was in school, but one of her roommates did not like it because she found it too difficult.