David H. DELPHENICH
Physics Department,
Bethany College,
Lindsborg, KS 67456,
USA
E-mail: delphenichd@bethanylb.edu

Symmetries of pre-metric electromagnetism

Abstract:
The equations of pre-metric electromagnetism are presented as an exterior differential system on the bundle of 2-forms over spacetime, and the symmetries of that system are discussed in various cases of the electromagnetic constitutive law. The way that this reinforces the role of projective geometry in pre-metric electromagnetism is discussed.