PROF. THOMSON'S book will do good in many ways. Even its title will correct a wrong impression which very generally prevails, to the effect that just so much of the fundamentals and facts of the ...

Consider the set S n of all rearrangments of the numbers 1,2,3,...,n. We may represent each rearrangement in S n by diagrams like the ones below, where we use oriented strings to indicate where each ...