{ "cell_id": 1122815849851778574, "cells": [ { "cell_id": 5978568215711204063, "cell_origin": "client", "cell_type": "latex", "cells": [ { "cell_id": 9163289818544044159, "cell_origin": "client", "cell_type": "latex_view", "source": "\\section*{Derivatives and implicit dependence on coordinates}\n\nThere is no fixed notation for derivatives; as with all other objects\nyou have to declare derivatives by associating a property to them, in\nthis case the \\prop{Derivative} property. " } ], "hidden": true, "source": "\\section*{Derivatives and implicit dependence on coordinates}\n\nThere is no fixed notation for derivatives; as with all other objects\nyou have to declare derivatives by associating a property to them, in\nthis case the \\prop{Derivative} property. " }, { "cell_id": 3121771876375322580, "cell_origin": "client", "cell_type": "input", "cells": [ { "cell_id": 17189132776906135827, "cell_origin": "server", "cell_type": "latex_view", "source": "\\begin{dmath*}{}\\text{Property Derivative attached to~}\\backslash\\texttt{nabla}\\{\\#\\}.\\end{dmath*}" } ], "source": "\\nabla{#}::Derivative;" }, { "cell_id": 13092358405604264614, "cell_origin": "client", "cell_type": "latex", "cells": [ { "cell_id": 13903985434684835252, "cell_origin": "client", "cell_type": "latex_view", "source": "Derivative objects can be used in various ways. You can just write the\nderivative symbol, as in" } ], "hidden": true, "source": "Derivative objects can be used in various ways. You can just write the\nderivative symbol, as in" }, { "cell_id": 18151900650212757933, "cell_origin": "client", "cell_type": "input", "cells": [ { "cell_id": 13634587081560003361, "cell_origin": "server", "cell_type": "latex_view", "cells": [ { "cell_id": 17401122873979242133, "cell_origin": "server", "cell_type": "input_form", "source": "\\nabla(A_{\\mu})" } ], "source": "\\begin{dmath*}{}\\nabla{A_{\\mu}}\\end{dmath*}" } ], "source": "ex:=\\nabla{ A_{\\mu} };" }, { "cell_id": 2535925725272172629, "cell_origin": "client", "cell_type": "latex", "cells": [ { "cell_id": 2703885803720580789, "cell_origin": "client", "cell_type": "latex_view", "source": "Or you can write the coordinate with\nrespect to which the derivative is taken," } ], "hidden": true, "source": "Or you can write the coordinate with\nrespect to which the derivative is taken," }, { "cell_id": 16893005691693910276, "cell_origin": "client", "cell_type": "input", "cells": [ { "cell_id": 6265159977008670288, "cell_origin": "server", "cell_type": "latex_view", "source": "\\begin{dmath*}{}\\text{Property Coordinate attached to~}s.\\end{dmath*}" }, { "cell_id": 2508463848585078013, "cell_origin": "server", "cell_type": "latex_view", "source": "\\begin{dmath*}{}\\text{Property Depends attached to~}A_{\\mu}.\\end{dmath*}" }, { "cell_id": 9585809248094876254, "cell_origin": "server", "cell_type": "latex_view", "cells": [ { "cell_id": 14661015508918667345, "cell_origin": "server", "cell_type": "input_form", "source": "\\nabla_{s}(A_{\\mu})" } ], "source": "\\begin{dmath*}{}\\nabla_{s}{A_{\\mu}}\\end{dmath*}" } ], "source": "s::Coordinate;\nA_{\\mu}::Depends(s);\nex:=\\nabla_{s}{ A_{\\mu} };" }, { "cell_id": 10153963060502655636, "cell_origin": "client", "cell_type": "latex", "cells": [ { "cell_id": 10916447968963342696, "cell_origin": "client", "cell_type": "latex_view", "source": "Finally, you can use an index as the subscript argument, as in" } ], "hidden": true, "source": "Finally, you can use an index as the subscript argument, as in" }, { "cell_id": 13561250281933297262, "cell_origin": "client", "cell_type": "input", "cells": [ { "cell_id": 2893963764896938419, "cell_origin": "server", "cell_type": "latex_view", "source": "\\begin{dmath*}{}\\text{Property Indices(position=free) attached to~}\\left[\\mu, \\discretionary{}{}{}\\nu\\right].\\end{dmath*}" }, { "cell_id": 10286893870653739756, "cell_origin": "server", "cell_type": "latex_view", "cells": [ { "cell_id": 8500921658553144632, "cell_origin": "server", "cell_type": "input_form", "source": "\\nabla_{\\nu}(A_{\\mu})" } ], "source": "\\begin{dmath*}{}\\nabla_{\\nu}{A_{\\mu}}\\end{dmath*}" } ], "source": "{ \\mu, \\nu }::Indices(vector);\nex:=\\nabla_{\\nu}{ A_{\\mu} };" }, { "cell_id": 10444583949408313065, "cell_origin": "client", "cell_type": "latex", "cells": [ { "cell_id": 4530724075209643387, "cell_origin": "client", "cell_type": "latex_view", "source": "(in which case the first line is, for the purpose of using the\nderivative operator, actually unnecessary). " } ], "hidden": true, "source": "(in which case the first line is, for the purpose of using the\nderivative operator, actually unnecessary). " }, { "cell_id": 13397161166768324625, "cell_origin": "client", "cell_type": "latex", "cells": [ { "cell_id": 17715485633604521333, "cell_origin": "client", "cell_type": "latex_view", "source": "The main point of associating the \\prop{Derivative} property to an\nobject is to make the object obey the Leibnitz or product rule, as\nillustrated by the following example," } ], "hidden": true, "source": "The main point of associating the \\prop{Derivative} property to an\nobject is to make the object obey the Leibnitz or product rule, as\nillustrated by the following example," }, { "cell_id": 4282409426609146563, "cell_origin": "client", "cell_type": "input", "cells": [ { "cell_id": 17039843437785172514, "cell_origin": "server", "cell_type": "latex_view", "source": "\\begin{dmath*}{}\\text{Property Derivative attached to~}\\backslash\\texttt{nabla}\\{\\#\\}.\\end{dmath*}" }, { "cell_id": 12960000548412277736, "cell_origin": "server", "cell_type": "latex_view", "cells": [ { "cell_id": 535790888793878903, "cell_origin": "server", "cell_type": "input_form", "source": "\\nabla(A_{\\mu} B_{\\nu})" } ], "source": "\\begin{dmath*}{}\\nabla\\left(A_{\\mu} B_{\\nu}\\right)\\end{dmath*}" }, { "cell_id": 12457032370277415749, "cell_origin": "server", "cell_type": "latex_view", "cells": [ { "cell_id": 3795438018106939319, "cell_origin": "server", "cell_type": "input_form", "source": "\\nabla(A_{\\mu}) B_{\\nu} + A_{\\mu} \\nabla(B_{\\nu})" } ], "source": "\\begin{dmath*}{}\\nabla{A_{\\mu}} B_{\\nu}\\discretionary{}{}{}+A_{\\mu} \\nabla{B_{\\nu}}\\end{dmath*}" } ], "source": "\\nabla{#}::Derivative;\nex:= \\nabla{ A_{\\mu} * B_{\\nu} };\nproduct_rule(_);" }, { "cell_id": 8677916216204324123, "cell_origin": "client", "cell_type": "latex", "cells": [ { "cell_id": 17244218890176750790, "cell_origin": "client", "cell_type": "latex_view", "source": "This behaviour is a consequence of the fact that \\prop{Derivative}\nderives from \\prop{Distributable}. Note that the\n\\prop{Derivative} property does not automatically give you \ncommuting derivatives, so that you can e.g.~use it to write covariant\nderivatives. " } ], "hidden": true, "source": "This behaviour is a consequence of the fact that \\prop{Derivative}\nderives from \\prop{Distributable}. Note that the\n\\prop{Derivative} property does not automatically give you \ncommuting derivatives, so that you can e.g.~use it to write covariant\nderivatives. " }, { "cell_id": 4266922430318706841, "cell_origin": "client", "cell_type": "latex", "cells": [ { "cell_id": 7753763602494058227, "cell_origin": "client", "cell_type": "latex_view", "source": "More specific derivative types exist too. An example are partial\nderivatives, declared using the \\prop{PartialDerivative} property.\nPartial derivatives are commuting and therefore automatically\nsymmetric in their indices," } ], "hidden": true, "source": "More specific derivative types exist too. An example are partial\nderivatives, declared using the \\prop{PartialDerivative} property.\nPartial derivatives are commuting and therefore automatically\nsymmetric in their indices," }, { "cell_id": 1000836246543036704, "cell_origin": "client", "cell_type": "input", "cells": [ { "cell_id": 7592315176139174518, "cell_origin": "server", "cell_type": "latex_view", "source": "\\begin{dmath*}{}\\text{Property PartialDerivative attached to~}\\backslash\\texttt{partial}\\{\\#\\}.\\end{dmath*}" }, { "cell_id": 1289170573850456116, "cell_origin": "server", "cell_type": "latex_view", "source": "\\begin{dmath*}{}\\text{Property Indices(position=free) attached to~}\\left[a, \\discretionary{}{}{}b, \\discretionary{}{}{}m, \\discretionary{}{}{}n\\right].\\end{dmath*}" }, { "cell_id": 11151070317708428483, "cell_origin": "server", "cell_type": "latex_view", "source": "\\begin{dmath*}{}\\text{Property Symmetric attached to~}C_{m n}.\\end{dmath*}" }, { "cell_id": 15420425853360909320, "cell_origin": "server", "cell_type": "latex_view", "cells": [ { "cell_id": 16823369671527784028, "cell_origin": "server", "cell_type": "input_form", "source": "T^{b a} \\partial_{a b}(C_{m n} D_{n m})" } ], "source": "\\begin{dmath*}{}T^{b a} \\partial_{a b}\\left(C_{m n} D_{n m}\\right)\\end{dmath*}" } ], "source": "\\partial{#}::PartialDerivative;\n{a,b,m,n}::Indices(vector);\nC_{m n}::Symmetric;\nex:=T^{b a} \\partial_{a b}( C_{m n} D_{n m} );" }, { "cell_id": 17184423938730932951, "cell_origin": "client", "cell_type": "input", "cells": [ { "cell_id": 14011557080814126640, "cell_origin": "server", "cell_type": "latex_view", "cells": [ { "cell_id": 7167017290773373763, "cell_origin": "server", "cell_type": "input_form", "source": "T^{a b} \\partial_{a b}(C_{m n} D_{m n})" } ], "source": "\\begin{dmath*}{}T^{a b} \\partial_{a b}\\left(C_{m n} D_{m n}\\right)\\end{dmath*}" } ], "source": "canonicalise(_);" }, { "cell_id": 17585485201075769805, "cell_origin": "client", "cell_type": "input", "source": "" } ], "description": "Cadabra JSON notebook format", "version": 1.0 }