Abstract. There is a certain family of conformally invariant first order elliptic systems which include the Dirac operator as its first and simplest member. Their general definition is given and some of their basic properties are described. A special attention is paid to the Rarita-Schwinger operator, the second simplest operator in the row. Its basic properties are described in more details. In the last part indices of discussed operators are computed.
AMSclassification. 58G25, 53C25
Keywords. Conformally invariant operators, Rarita-Schwinger operator