This is a textbook for a one-term course whose goal is to ease the
transition from lower-division calculus courses to upper-division
courses in linear and abstract algebra, real and complex analysis,
number theory, topology, combinatorics, and so on. Without such a
"bridge" course, most upper- division instructors feel the need to start
their courses with the rudiments of logic, set theory, equivalence
relations, and other basic mathematical raw materials before getting on
with the subject at hand. Students who are new to higher mathematics are
often startled to discover that mathematics is a subject of ideas, and
not just formulaic rituals, and that they are now expected to understand
and create mathematical proofs. Mastery of an assortment of technical
tricks may have carried the students through calculus, but it is no
longer a guarantee of academic success. Students need experience in
working with abstract ideas at a nontrivial level if they are to achieve
the sophisticated blend of knowledge, disci- pline, and creativity that
we call "mathematical maturity. " I don't believe that "theorem-proving"
can be taught any more than "question-answering" can be taught.
Nevertheless, I have found that it is possible to guide stu- dents
gently into the process of mathematical proof in such a way that they
become comfortable with the experience and begin asking them- selves
questions that will lead them in the right direction.