An Algorithm Using Symbolic Techniques for the
Bel-Petrov Classification of Gravitational Fields
In this note, an algorithm is presented for the
symbolic calculation of certain algebraic invariants 
of the Weyl tensor which permits the determination
of the Bel-Petrov types of a gravitational field. 
 This algorithm, although more specialized than that
of D'Inverno and Russell-Clark, requires neither 
the use of a special coordinate system nor the spin coefficient
formalism.  The algorithm has been implemented 
in FORMAC and is designed to complete the classification
scheme proposed by Petrov in his book.  An appendix 
contains examples illustrating the use of the algorithm.
CACM September, 1978
Harris, R.A.
Zund, J.D.
