Additive Combinatorics is a lovely book and so far I can understand it, though I'm only on Chapter One!
Sermon this morning was on the calling of Peter and Andrew. It's interesting that in Matthew Jesus says "I will make you fishers of men" and the Greek word haleeis is the ordinary word for fishermen, but Luke has "henceforth you will be catching men" and the word is zwgrwn which means "taking alive" or indeed taking into life (Mark is like Matthew but has "I will make you become fishers of men". Of course these are not "discrepencies" because the Gospels are portraits not transcripts, and anyway Jesus would have spoken in Aramaic). Life is a big theme of Luke's (he was after all a physician according to tradition) and his emphasis is clearly that the disciples are bringing people into true life.