(non-)shrinking semantics of aggregates

Hi all,

I hope someone of you can help in answering my question: In [1] (e.g. page 8 and 11) I read about "shrinking" and "non-shrinking semantics" of aggregates with a reference to the paper at [2]. However, in [2] the word "shrinking" does not appear a single time.

So I wonder, if the reference is a mistake, or maybe I'm just blind and can't find the explanation in [2]. After all, I just would like to know where to find a proper definition of shrinking and non-shrinking semantics.

Thanks!

[1] Scharrenbach, T., Urbani, J., Margara, A., Della Valle, E., & Bernstein, A. (2013). Seven commandments for benchmarking semantic flow processing systems. In The Semantic Web: Semantics and Big Data (pp. 305-319). Springer Berlin Heidelberg. URL: http://eswc-conferences.org/sites/default/files/papers2013/scharrenbach.pdf
[2] Barbieri, D. F., Braga, D., Ceri, S., Della Valle, E., & Grossniklaus, M. (2010). Incremental reasoning on streams and rich background knowledge (pp. 1-15). Springer Berlin Heidelberg. Chicago. URL: http://kops.uni-konstanz.de/bitstream/handle/123456789/25310/Barbieri_253103.pdf

Best,
Peter