 Definition 4.1 (Microsymmetry Group) A microsymmetry of a structural field (Strukturfeld) at a point \(p \in M\) is a local diffeomorphism that takes \(p \in M\) into \(p\) and preserves the structural field at \(p \in M\).  The microsymmetry group of a field at \(p \in M\) is the group of its microsymmetries at \(p \in M\) under the operation of composition. 