7. A method according to claim 1 wherein said matching step b comprises the step of: building an isomorphism between two subsets of 0-cells by several successive runs of different filtering procedures which reject certain potential matches if they are recognized as invalid.
26. A method according to claim 7 comprising the step of: a. if an isomorphism between factor-2-cells can be defined, verifying that the isomorphic loops of factor-1-cells contain inside themselves sets of the other (or none) isomorphic loops; b. rejecting the loops which do not meet the conditions of paragraph (a) above.