[{"n": "Lorentz covariance", "u": "/e/relativity-and-spacetime/lorentz-covariance/", "s": "Property of spacetime ensuring equations hold in all inertial frames."}, {"n": "Lorentz factor", "u": "/e/relativity-and-spacetime/lorentz-factor/", "s": "Dimensionless factor quantifying relativistic time dilation and length contraction."}, {"n": "Lorenz gauge condition", "u": "/e/relativity-and-spacetime/lorenz-gauge-condition/", "s": "A Lorentz-invariant gauge condition for electromagnetic potentials."}, {"n": "Minkowski spacetime", "u": "/e/relativity-and-spacetime/minkowski-spacetime/", "s": "Four-dimensional model unifying space and time in special relativity."}, {"n": "Moving magnet and conductor problem", "u": "/e/relativity-and-spacetime/moving-magnet-and-conductor-problem/", "s": "A thought experiment on relativity and electromagnetism."}, {"n": "No-hair theorem", "u": "/e/relativity-and-spacetime/no-hair-theorem/", "s": "Black holes are fully described by mass, charge, and spin."}, {"n": "Penrose diagram", "u": "/e/relativity-and-spacetime/penrose-diagram/", "s": "A conformal diagram mapping causal structure of spacetime."}, {"n": "Penrose–Hawking singularity theorems", "u": "/e/relativity-and-spacetime/penrose-hawking-singularity-theorems/", "s": "Theorems proving gravitational singularities are inevitable under general relativity."}, {"n": "Poincaré group", "u": "/e/relativity-and-spacetime/poincar-group/", "s": "Isometry group of Minkowski spacetime, fundamental to special relativity."}, {"n": "Principle of covariance", "u": "/e/relativity-and-spacetime/principle-of-covariance/", "s": "Principle requiring covariant formulation of physical laws."}, {"n": "Principle of locality", "u": "/e/relativity-and-spacetime/principle-of-locality/", "s": "An object is influenced directly only by its immediate surroundings."}, {"n": "Problem of time", "u": "/e/relativity-and-spacetime/problem-of-time/", "s": "A conflict between quantum mechanics and general relativity over time."}, {"n": "Proper time", "u": "/e/relativity-and-spacetime/proper-time/", "s": "Proper time is the time measured by a clock along its world line."}, {"n": "Mass–energy equivalence", "u": "/e/relativity-and-spacetime/mass-energy-equivalence/", "s": "Mass and energy are equivalent, related by the speed of light squared."}, {"n": "Relativity of simultaneity", "u": "/e/relativity-and-spacetime/relativity-of-simultaneity/", "s": "Distant simultaneity depends on the observer's reference frame."}, {"n": "Retarded time", "u": "/e/relativity-and-spacetime/retarded-time/", "s": "Emission time accounting for light's finite speed."}, {"n": "Spacetime", "u": "/e/relativity-and-spacetime/spacetime/", "s": "A four-dimensional continuum fusing space and time."}, {"n": "Spacetime diagram", "u": "/e/relativity-and-spacetime/spacetime-diagram/", "s": "Graphical tool illustrating spacetime geometry in special relativity."}, {"n": "Tests of general relativity", "u": "/e/relativity-and-spacetime/tests-of-general-relativity/", "s": "Observational evidence confirming Einstein's theory of general relativity."}, {"n": "Twin paradox", "u": "/e/relativity-and-spacetime/twin-paradox/", "s": "A thought experiment on relativistic time dilation and aging."}, {"n": "Time in physics", "u": "/e/relativity-and-spacetime/time-in-physics/", "s": "Time is defined by measurement and is a fundamental quantity in physics."}, {"n": "Wheeler–Feynman absorber theory", "u": "/e/relativity-and-spacetime/wheeler-feynman-absorber-theory/", "s": "Time-symmetric electrodynamics with no independent electromagnetic field."}]