Notes for the preparation of a lesson. Spin matrices.

Draft for a note in the paper on the influence of archetype in Kepler's theory.

Graph of specific heat vs. Temperature.

Notes and calculations on Hamilton-principle. Palatini.

Notes and calculations on high temperatures. Related to an article by W. Opechowski in Physica.

Notes and calculations on homogeneous and non-homogeneous Lorentz gorups.

Lorentz groups.

Correction of a student's work on wave equations.

Notes and calculations. Lorentz groups. Rotation matrices.