Streams are Forever

Just like diamonds, streams are forever. They are also ubiquitous, arising in theoretical computer science (formal languages and functional programming), mathematics (number theory), and engineering (signal processing). Also in business computing applications streams are important. Here one can think of the streams of data queries flowing into search engines, or streams of financial data processed by financial organizations. In this paper, we describe a number of aspects of streams that we have encountered and studied during the last years.