Who was the Dutch theoretical physicist that created the 't Hooft η symbol?
't Hooft symbol The 't Hooft η symbol is a symbol which allows one to express the generators of the SU(2) Lie algebra in terms of the generators of Lorentz algebra. The symbol is a blend between the Kronecker delta and the Levi-Civita symbol. It was introduced by Gerard 't Hooft. It is used in the construction of the BPST instanton.
Tonti diagram The Tonti diagram, created by the Italian physicist and mathematician Enzo Tonti, is a diagram that classifies variables and equations of physical theories of classical and relativistic physics. The theories involved are: "particle dynamics, analytical mechanics, mechanics of deformable solids, fluid mechanics, electromagnetism, gravitation, heat conduction," and "irreversible thermodynamics". The classification stems from the observation that each physical variable has a well-defined association with a space and a time element, as shown in Fig. 1, which can be grasped from the corresponding global variable and from its measuring process.