[seqfan] Two math theses in comparison

[Richard Mathar]

I stumbled across two recent math PhD theses,
http://perso.ens-lyon.fr/mioara.joldes/these/theseJoldes_22.09.2011.pdf
and
http://www.normalesup.org/~mezzarobba/these/these-mezzarobba.pdf
and I am wondering: is it quite usual in Mathematics that the content of two
theses (although written in different languages) has such a massive overlap?

Richard