I'm exploring A Walk Through Combinatorics by Bóna. I've come across a notation that isn't explained in the book, but that I have not seen before. Its first appearance is in the question, "how many ways are there to permute the elements of the set [7] so that an even number is in the first position?"
My instinct is that, perhaps, the set [n] here is meant to denote the natural numbers through 7, so, {1,2,3,4,5,6,7}. I'm not sure, though.
Sorry this is probably a relatively basic question - I just got through a text on mathematical proofs, and this is my first proof-based text I'm attempting to tackle!