Elementary calculus in chevalley groups over rings

The article studies structure theory of chevalley groups over commutative rings. main results of the article are relative dilation and local-global principles. and an economic set of generators of relative el-ementary subgroup. these statements proved by computations with ele-mentary unipotents (hence the title) are very important in further develop-ment of the subject. no restrictions on the ground ring or the root system φ are imposed except that the rank of φ is not less than 2. the results improve previous results in the area. the article contains a brief survey of the subject,some gaps in proofs or incorrect references are discussed. proofs of some known related results are substantially simplied.