
Description


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The software includes a variety of homotopy operators for the de Rham and variational bicomplexes; extensive capabilities for computing with the NewmanPenrose and spinor formalisms in general relativity; programs for analyzing the structure of general and semisimple Lie algebras; programs for finding symmetries of tensor fields and other geometric structures; and programs for construction of a solvable Lie group from its Lie algebra.

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Computations may be performed in user specified frames. One can also compute with abstract differential forms, that is, with differential forms and their structure equations defined without reference to any underlying system of coordinates.

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Also included are extensive tables of Lie algebras, Lie algebras of vectors, differential equations, and spacetime metrics taken from the mathematics and mathematical physics literature.

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The DifferentialGeometry package includes a comprehensive collection of Lessons and Tutorials. The lessons worksheets provide a systematic approach to learning the commands in the DifferentialGeometry, Tensor, LieAlgebras, and JetCalculus subpackages. Each lesson contains a set of exercises which range in difficult from simple computational exercises to programming exercises. Solutions are given. The tutorials present specialized applications of the DifferentialGeometry package.

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The DifferentialGeometry package is based upon the Vessiot package developed by I. M. Anderson, Florin Catrina, Sydney Chamberlain, Cinnamon Hillyard, Jeff Humphries, Jamie Jorgensen, Charles Miller, and Charles Torre at Utah State University. The redesign and expansion of Vessiot to DifferentialGeometry for Maple 11 was done by I. M. Anderson and E. S. ChebTerrab. See also References.

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Each command in the DifferentialGeometry package can be accessed by using either the long form or the short form of the command name in the command calling sequence.



List of the DifferentialGeometry commands and subpackages


The following is a list of available commands and subpackages.
A brief description of the package's commands is as follows.
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&algmult: multiply two vectors in an algebra

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&minus: find the difference between two vectors, differential forms or tensors.

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&mult: multiply a vector, differential form or tensor by a Maple expression.

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&plus: add two vectors, differential forms or tensors.

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&tensor: calculate the tensor product of two tensors.

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&wedge: calculate the exterior product of two differential forms.

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Annihilator: find the subspace of vectors (or 1forms) whose interior product with a given list of 1forms (or vectors) vanish.

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Convert: change the presentations or internal representations of various geometric objects.

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DGIm: find the imaginary part of a vector, a tensor or differential form; find the imaginary part of a quaternion or octonion

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DGImageSpace: find the image space of a linear transformation acting on a vector space of vectors, differential forms, tensors

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DGNullSpace: find the null space of a linear transformation acting on a vector space of vectors, differential forms, tensors

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DGRe: find the real part of a vector, tensor or differential form; find the real part of a quaternion or octonion

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DGbasis: select a maximal linearly independent list of elements from a list of vectors, forms or tensors.

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DGconjugate: find the complex conjugate of a vector, tensor or differential form; find the conjugate of a quaternion or octonion

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DGsetup: initialize a coordinate system, frame, or Lie algebra.

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DGsolve: solve a list of tensor equations for an unknown list of tensors

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DGzip: form a linear combination, wedge product or tensor product of a list of vectors, forms or tensors.

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DeRhamHomotopy: the homotopy operator for the exterior derivative operator (the de Rham complex).

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DualBasis: calculate the dual basis to a given basis of vectors or 1forms.

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evalDG: evaluate a DifferentialGeometry expression.

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Flow: calculate the 1parameter group of diffeomorphisms (the flow) of a vector field.

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FrameData: calculate the structure equations for a generic (anholonomic) frame.

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GetComponents: find the coefficients of a vector, differential form or tensor with respect to a list of vectors, differential forms or tensors.

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GroupActions: a package for Lie groups and group actions on manifolds.

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Hook: the interior product of a vector or a list of vectors with a differential form.

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IntegrateForm: evaluate a pfold iterated integral of a differential pform.

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IntersectSubspaces: find the intersection of a list of vector subspaces of vectors, forms or tensors.

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JetCalculus: a package for the variational calculus on jet spaces.

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Library: a package of databases of Lie algebras, vector field systems, differential equations, and exact solutions in general relativity.

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LieAlgebras: a package for the symbolic analysis of Lie algebras.

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LieBracket: calculate the Lie bracket of two vector fields.

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LieDerivative: calculate the Lie derivative of a vector field, differential form or tensor with respect to a vector field.

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Preferences: set worksheet preferences for the DifferentialGeometry package.

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Pullback: pullback a differential pform by the Jacobian of a transformation.

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PullbackVector: find (if possible) a vector field whose pushforward by the Jacobian of a given transformation is a given vector field.

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Pushforward: pushforward a vector or a vector field by the Jacobian of a transformation.

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Tensor: a package for tensor analysis within the DifferentialGeometry environment.

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Tools: a small utility package for DifferentialGeometry.

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Transformation: create a transformation or mapping from one manifold to another.



