In (1916b) he criticized the role of the
equivalence principle in general relativity, which prompted a reply by Einstein in the same year.[8]
In (1918) he formulated the Kottler metric or Kottler spacetime (which has been described as "the only spherically symmetric solution of the
Einstein vacuum field equations with a
cosmological constant"[9]), as well as the Kottler-
Whittaker metric for a homogeneous gravitational field in flat spacetime.[7]
In (1922a, 1922b) he argued that one can formulate Maxwell's equations and Newton's law of gravitation independently of any
metric.[10]
In (1922c) he published the article "Gravitation und Relativitätstheorie" in Band 6 of
Klein's encyclopedia.
1922a: Newtonsches Gesetz und Metrik, Wiener Sitzungsberichte 2a, 131: 1-14. (English translation by David Delphenich:
Newton's laws and metrics)
1922b: Maxwellsche Gleichungen und Metrik, Wiener Sitzungsberichte 2a, 131: 119-146 (English translation by David Delphenich:
Maxwell’s equations and metrics)
In (1916b) he criticized the role of the
equivalence principle in general relativity, which prompted a reply by Einstein in the same year.[8]
In (1918) he formulated the Kottler metric or Kottler spacetime (which has been described as "the only spherically symmetric solution of the
Einstein vacuum field equations with a
cosmological constant"[9]), as well as the Kottler-
Whittaker metric for a homogeneous gravitational field in flat spacetime.[7]
In (1922a, 1922b) he argued that one can formulate Maxwell's equations and Newton's law of gravitation independently of any
metric.[10]
In (1922c) he published the article "Gravitation und Relativitätstheorie" in Band 6 of
Klein's encyclopedia.
1922a: Newtonsches Gesetz und Metrik, Wiener Sitzungsberichte 2a, 131: 1-14. (English translation by David Delphenich:
Newton's laws and metrics)
1922b: Maxwellsche Gleichungen und Metrik, Wiener Sitzungsberichte 2a, 131: 119-146 (English translation by David Delphenich:
Maxwell’s equations and metrics)