On Generators and Relations of Simple Groups of Lie Type

1. Introduction Let L be a simple Lie algebra over C, rank L>1, K a field, R.Steinberg proved a theorem (Cf.〔1〕 and 〔2〕 12.1) which leads to the definition ofUniversal Chevalley groups through generators and relations such that a simple Chevalley group is isomrphic to the quotient group of the corresponding Universal Chevalley group modulo its centre. Steiberg′s theorem playsan importent role in dealing with Chevalley groups.