Pafnuty Lvovich Chebyshev was a Russian mathematician and considered to be the founding father of Russian mathematics.

Coptic is a group of closely related Egyptian dialects, representing the most recent developments of the Egyptian language, and historically spoken by the Copts, starting from the third century AD in Roman Egypt. Coptic was supplanted by Arabic as the primary spoken language of Egypt following the Arab conquest of Egypt and was slowly replaced over the centuries. Coptic has no native speakers today, although it remains in daily use as the liturgical language of the Coptic Orthodox Church and of the Coptic Catholic Church. Innovations in grammar and phonology and the influx of Greek loanwords distinguish Coptic from earlier periods of the Egyptian language. It is written with the Coptic alphabet, a modified form of the Greek alphabet with several additional letters borrowed from the Demotic Egyptian script.