Holon of Gravitational Theories

A holon is a theoretical network that interrelates many kinds of theories. This holon seeks to bring together several of the lattices presented in the Exploratorium that comply with the same formalism and notation: supported by the same topology, a covariant formalism and coordinate-free notation. The data considers the classification of Thomas P. Sotiriou and Valerio Faraoni in f(R) theories of gravity, in the classification of Michael Friedman in Foundations of Space-Time Theories: Relativistic Physics and Philosophy of Science, in Clifford Will’s classification in Theory and Experiment on Gravitational Physics, and in the articles by Sergio Mendoza et al. (2013, 2016, 2018) on extended local and non-local theories.

Locate groups of theories, for example: those that follow a geodesic, those that have curvature = 0, or the node that selects metric theories only. What model would that node correspond to? Observe the theoretical evolution from left to right.