Grichka thesis : https://tel.archives-ouvertes.fr/tel-00001502/document
Igor thesis : https://tel.archives-ouvertes.fr/tel-00001503v1/document
Igor thesis : https://tel.archives-ouvertes.fr/tel-00001503v1/document
It's fine if you have a handful of equations in your text. But for a PhD in maths? Unacceptable.