1. It may have a non-principal axis rotation. 2. The main platform covers area of 24 hectares, following along two principal axis . 3. No evidence of a non-principal axis rotation ( NPAR ) was found. 4. The resulting crystal structure has hexagonal symmetry when viewed along a principal axis . ]] 5. However, no significant evidence of such a non-principal axis rotation could be found. 6. It is also a suspected tumbling asteroid, which show a non-principal axis rotation. 7. By convention, the axis of proper rotation of greatest order is defined as the principal axis . 8. Mathematically, the principal axis theorem is a generalization of the method of completing the square from elementary algebra. 9. In linear algebra and functional analysis, the principal axis theorem is a geometrical counterpart of the spectral theorem. 10. For triclinic, orthorhombic, and cubic crystal systems the axis designation is arbitrary and there is no principal axis .