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Hamilton's principle/Figure gallery

From The Invariance Itself
Revision as of 05:05, 9 September 2026 by BFP Rauch (talk | contribs) (1 revision imported)

Every figure in the volume, with the pages that carry it. This page is generated from the figure manifest, so it cannot fall out of step with what is shipped.

58 figures, 131 placements.

All figures are original to this volume. They are drawn as SVG and shipped as PNG; the reasons are given at the foot of this page.


The method

figure shows carried by
F-01 A true path and several comparison paths between fixed endpoints Hamilton's principle/Mathematics/Functionals and the space of paths · Hamilton's principle/Mathematics/The first variation · Hamilton's principle · Hamilton's principle/Explainers/Comparing paths
F-02 A one-parameter family of paths through the true path Hamilton's principle/Mathematics/The first variation · Hamilton's principle/Explainers/Comparing paths
F-03 A localised test function Hamilton's principle/Mathematics/The fundamental lemma · Hamilton's principle/Explainers/What the Euler-Lagrange equation says
F-04 A free endpoint and its natural boundary condition Hamilton's principle/Mathematics/Boundary terms and natural boundary conditions · Hamilton's principle/Explainers/Free ends
F-16 A needle variation Hamilton's principle/Mathematics/The Legendre condition · Hamilton's principle/Explainers/Is it really a minimum
F-39 The two rates the Euler-Lagrange equation balances Hamilton's principle/Mathematics/The Euler-Lagrange equation · Hamilton's principle/Explainers/What the Euler-Lagrange equation says
F-40 The boundary term left by integration by parts Hamilton's principle/Mathematics/The first variation · Hamilton's principle/Mathematics/Boundary terms and natural boundary conditions · Hamilton's principle/Explainers/Free ends
F-41 An endpoint free to lie on a curve Hamilton's principle/Mathematics/Boundary terms and natural boundary conditions
F-42 A corner in an extremal Hamilton's principle/Mathematics/Boundary terms and natural boundary conditions · Hamilton's principle/Mathematics/The Weierstrass excess function
F-43 A quantity conserved along the whole path Hamilton's principle/Mathematics/The Beltrami identity · Hamilton's principle/Explainers/Free ends
F-44 Varying one degree of freedom at a time Hamilton's principle/Mathematics/Several dependent variables · Hamilton's principle/Mathematics/Holonomic constraints · Hamilton's principle/Explainers/More than one variable · Hamilton's principle/Explainers/Constraints
F-56 From one independent variable to several Hamilton's principle/Mathematics/Several independent variables · Hamilton's principle/Explainers/More than one variable

Whether a path is best

figure shows carried by
F-05 Geodesics from a pole refocusing at the antipode Hamilton's principle/Mathematics/The Jacobi condition and conjugate points · Hamilton's principle/Applications/Geodesics · Hamilton's principle/Explainers/Where the minimum fails
F-07 The second variation changing sign as the interval lengthens Hamilton's principle/Mathematics/The second variation · Hamilton's principle/Explainers/Is it really a minimum
F-13 A sawtooth competitor close in position and far in slope Hamilton's principle/Mathematics/The Weierstrass excess function · Hamilton's principle/Explainers/Strong and weak
F-14 Two stationary light paths around a mass Hamilton's principle/Applications/The Einstein-Hilbert action · Hamilton's principle/Explainers/Where the minimum fails · Hamilton's principle/Explainers/Gravity from an action
F-17 Local penalty against accumulated reward Hamilton's principle/Mathematics/The second variation · Hamilton's principle/Explainers/Is it really a minimum
F-22 Geodesic behaviour on flat, spherical and saddle surfaces Hamilton's principle/Mathematics/The Jacobi condition and conjugate points · Hamilton's principle/Applications/Geodesics
F-34 The Weierstrass excess function as a gap above the tangent Hamilton's principle/Mathematics/The Weierstrass excess function · Hamilton's principle/Explainers/Strong and weak
F-49 The four conditions of the sufficiency theory Hamilton's principle/Mathematics/The Legendre condition · Hamilton's principle/Mathematics/The Weierstrass excess function · Hamilton's principle/Explainers/Strong and weak
F-50 Rays crossing a focus Hamilton's principle/Applications/The Feynman path integral · Hamilton's principle/Mathematics/The Jacobi condition and conjugate points · Hamilton's principle/Explainers/Waves and rays

Structure

figure shows carried by
F-10 The Legendre transform as a tangent-line description Hamilton's principle/Mathematics/The Legendre transform · Hamilton's principle/Explainers/Reading a curve two ways
F-11 Phase portrait of a pendulum Hamilton's principle/Mathematics/The Hamiltonian and Hamilton's equations · Hamilton's principle/Explainers/The Hamiltonian
F-12 Wavefronts and the rays orthogonal to them Hamilton's principle/Mathematics/The Hamilton-Jacobi equation · Hamilton's principle/Applications/The optical-mechanical analogy · Hamilton's principle/Explainers/Waves and rays
F-24 Lagrangian and Hamiltonian descriptions compared Hamilton's principle/Mathematics/The Hamiltonian and Hamilton's equations · Hamilton's principle/Explainers/The Hamiltonian
F-25 Action on the true motion as a function of its endpoints Hamilton's principle/Mathematics/Action as a function of its endpoints · Hamilton's principle/Explainers/Action from the endpoints
F-32 From n second-order equations to one partial differential equation Hamilton's principle/Mathematics/The Hamilton-Jacobi equation · Hamilton's principle/Explainers/Waves and rays
F-36 What each action principle holds fixed Hamilton's principle/Mathematics/Abbreviated action: Maupertuis versus Hamilton · Hamilton's principle/Explainers/Two different actions
F-38 The optical-mechanical dictionary Hamilton's principle/Applications/The optical-mechanical analogy · Hamilton's principle/Explainers/Light and particles
F-48 The empty corner of the optical-mechanical analogy Hamilton's principle/Applications/The optical-mechanical analogy · Hamilton's principle/Explainers/Light and particles · Hamilton's principle/History/Hamilton 1834 and 1835

Symmetry

figure shows carried by
F-09 Symmetry to conservation, four examples Hamilton's principle/Mathematics/Noether's first theorem · Hamilton's principle/Explainers/Symmetry and conservation
F-26 Counting physical polarisations from gauge redundancy Hamilton's principle/Applications/The electromagnetic Lagrangian · Hamilton's principle/Explainers/Electromagnetism from an action
F-37 Identities among field equations from a local symmetry Hamilton's principle/Mathematics/Noether's second theorem · Hamilton's principle/Applications/The electromagnetic Lagrangian · Hamilton's principle/Explainers/When symmetry is local
F-51 Locality: influence passing from neighbour to neighbour Hamilton's principle/Applications/Classical field theory · Hamilton's principle/Explainers/Fields

Worked problems

figure shows carried by
F-06 The brachistochrone as a cycloid Hamilton's principle/Applications/The brachistochrone
F-08 Snell's law from stationary time Hamilton's principle/Applications/Fermat's principle · Hamilton's principle/Explainers/Light and particles
F-15 Phases adding near the stationary path and cancelling elsewhere Hamilton's principle/Applications/The Feynman path integral · Hamilton's principle/Explainers/Sum over histories
F-18 A constraint force normal to the permitted motion Hamilton's principle/Mathematics/Holonomic constraints · Hamilton's principle/History/d'Alembert and virtual work · Hamilton's principle/Explainers/Constraints
F-19 Tension in a swinging load Hamilton's principle/Mathematics/Lagrange multipliers · Hamilton's principle/Explainers/Multipliers
F-20 Fixed perimeter, varying area Hamilton's principle/Mathematics/Isoperimetric problems · Hamilton's principle/Explainers/Fixed length problems
F-23 A catenary and the directrix from which its tension is measured Hamilton's principle/Applications/The catenary · Hamilton's principle/Explainers/Free ends
F-27 Stability of rotation about the three principal axes Hamilton's principle/Applications/The rigid body
F-28 Fundamental modes with both ends fixed and with one end free Hamilton's principle/Applications/Continuum systems: the vibrating string · Hamilton's principle/Explainers/Free ends
F-29 Local conservation as a flow across a boundary Hamilton's principle/Applications/Classical field theory · Hamilton's principle/Explainers/Fields
F-30 Lambert's theorem: chord and sum of radii Hamilton's principle/Applications/Central force and the Kepler problem · Hamilton's principle/Explainers/Action from the endpoints
F-31 A bead chain approaching a continuous string Hamilton's principle/Applications/Continuum systems: the vibrating string · Hamilton's principle/Explainers/More than one variable
F-33 D'Alembert's principle: dynamics rewritten as statics Hamilton's principle/History/d'Alembert and virtual work · Hamilton's principle/Explainers/Constraints
F-35 A two-parameter family for an isoperimetric problem Hamilton's principle/Mathematics/Isoperimetric problems · Hamilton's principle/Explainers/Fixed length problems
F-45 Free fall as a straight path in a curved geometry Hamilton's principle/Applications/The Einstein-Hilbert action · Hamilton's principle/Explainers/Gravity from an action
F-46 Maxwell's equations split into dynamics and identities Hamilton's principle/Applications/The electromagnetic Lagrangian · Hamilton's principle/Explainers/Electromagnetism from an action
F-47 The effective potential of a central-force problem Hamilton's principle/Applications/Central force and the Kepler problem · Hamilton's principle/Applications/The rigid body
F-52 The boundary term in one dimension and in a field Hamilton's principle/Mathematics/Several independent variables · Hamilton's principle/Applications/The Einstein-Hilbert action · Hamilton's principle/Explainers/Gravity from an action

History and method

figure shows carried by
F-21 Chronology of the action principle Hamilton's principle/Chronology · Hamilton's principle
F-53 The three provenance classes, and the empty one Hamilton's principle/Sources
F-54 Four states an electronic source can be in Hamilton's principle/Sources · Hamilton's principle/History/Least time before least action
F-55 Three modernised statements attributed to their authors Hamilton's principle/Sources · Hamilton's principle/History/Least time before least action · Hamilton's principle/History/Maupertuis and the 1744 memoir · Hamilton's principle/History/Euler and the Methodus inveniendi
F-57 Transcribed against corroborated Hamilton's principle/Sources · Hamilton's principle/History/Maupertuis and the 1744 memoir
F-58 The two long gaps in the subject's history Hamilton's principle/Chronology · Hamilton's principle/History/Lagrange and the Mecanique analytique · Hamilton's principle/History/Jacobi · Hamilton's principle/History/Feynman 1948 · Hamilton's principle

Note on format

The volume ships raster figures rather than vector ones. A MediaWiki install accepts PNG with no configuration change, while SVG needs the upload extension list altered and the rasteriser bypassed. The masters are vector and the PNGs are rendered from them at twice the display size.

Every figure carries an opaque background, so the set reads consistently on a light skin and sits as a light panel on a dark one. That trade was chosen, not defaulted.