1.Concurrency is easy…? ( http://armstrongonsoftware.blogspot.com/2006/08/concurrency-is-easy.html ) 2.Sequential Programming -module(factorial). -export([factoriala/1, factorialb/1, factorialc/1, factoriald/1]). %Simplest: factoriala(0) -> 1; factoriala(N) -> N * factoriala(N - 1). %Using function guards: factorialb(0) -> 1; factorialb(N) when N > 0 -> N * factorialb(N - 1). %Using if: factorialc(N) -> if N == 0 -> 1; N > 0 -> N * factorialc(N - 1) end. %Using case: factoriald(N) -> case N of 0 -> 1; N when N > 0 -> N * factoriald(N - 1) end. -module(set). -export([new/0, add_element/2, del_element/2,is_element/2, is_empty/1, union/2, intersection/2]). new() -> []. is_element(H, [H|_]) -> true; is_element(H, [_|Set]) -> is_element(H, Set); is_element(_, []) -> false. is_empty([]) -> true; is_empty(_) -> false add_element(X, Set) -> case is_element(X, Set) o...