RICCI Changes.txt The list below shows all significant changes made to the package since the first beta release. 1/7/00 Version 1.34: Minor fixes to allow Ricci to work with Mathematica 4.0: Treated Tr as a system symbol, with Protect/Unprotect around definitions; Replaced Literal by HoldPattern throughout. 6/30/99 Version 1.33: Fixed the TangentBundle function so that it always assumes $DefaultTangentBundle for "generic" tensors whose bundle is denoted "Any". This allows BasisExpand to work correctly with expressions such as Del(Tor.X). 1/2/98 Version 1.32: Fixed bug in parenthesizing output expressions 8/18/97 Version 1.31: Fixed bug inserting indices in Del[x,Connection->c] 2/11/97 Version 1.3: Minor modifications to enable use with Mathematica 3.0. 4/19/95 J. Lee (Version 1.2.1) * Corrected omission of usage messages from released version. 4/14/95 J. Lee * Version 1.2 released. 2/17/95 J. Lee * Made tensor simplification functions return Null if called in error with no arguments. 12/29/94 J. Lee * Corrected DefineConstant[x,Type->Positive] 12/14/94 J. Lee * Fixed incorrect handling of Del[x,Metric->g] and Div[x,Metric->g] * Rewrote the algorithm for TensorExpand to make it much faster on expressions involving many factors. 7/11/94 J. Lee * Make DefineRelation omit 1-dimensional bundle indices from the list of dummy variables in its Module. 7/7/94 J. Lee * Correct handling of dummy variables in the Module created by DefineRule and DefineRelation. 7/1/94 J. Lee * Make Kronecker[L[z1],U[z2]] = 1 for 1-dimensional bundles. 5/31/94 J. Lee * Corrected code for Alt and Sym to correctly handle symmetric products of tensors on 1-dimensional bundles. 3/23/94 J. Lee * Added rules for Conjugate[RiemannTensor], Conjugate[RicciTensor], and Conjugate[ScalarCurv]. 11/25/93 J. Lee * Fix bug in DefineBundle.m in processing of BasisName. 9/27/93 J. Lee * Change all Ricci filenames to have no more than 8 characters, for compatibility with DOS. 7/15/93 J. Lee * Change DefineRule and DefineRelation so they create a "Module" for each rule or relation defined; this prevents conflicts with user-defined indices such as i1, i2, etc. 2/25/93 J. Lee * Fixed bug in Dot that did not allow use of Mathematica's internal Dot function for lists. * Fixed bug in DefineBundle that didn't correctly set components of the metric on a 1-dimensional bundle to 1 when OrthonormalFrame -> True. * Made metric components -1 when OrthonormalFrame -> True and PositiveDefinite -> False on a 1-dimensional bundle. 2/12/93 J. Lee * Fixed bug in InsertIndices that caused incorrect error message when wrong number of indices is inserted into a tensor. 8/24/92 J. Lee * Version 1.0 released. 8/21/92 J. Lee * Added "CurvToConnRule". * Added "CommutingFrame" option for DefineBundle. * Changed interpretation of Type option for DefineConstant, DefineMathFunction, DefineTensor: these functions now accept Type->{Positive,Real} etc. instead of Type->PositiveReal. * Added "Declare". * Eliminated "CorrectVariances", and replaced it with the Mode->OneDims option of "CorrectAllVariances". * Changes the OneDims->False option of AbsorbMetrics to Mode->NoOneDims. 8/13/92 J. Lee * Added "ConnToMetricRule". * Made UndefineBundle automatically undefine the Riemann, Ricci, and Scalar curvature tensors when undefining a Riemannian tangent bundle. 8/12/92 J. Lee * Fixed various bugs relating to non-default metrics and connections on a direct sum of bundles. 8/8/92 J. Lee * Fixed BasisGather so it recognizes both x and -x. This is necessary for expressions like ExtdStar[w] which begin with a minus sign. 8/6/92 J. Lee * Added rules to compute derivatives of components of inverse tensors and inverse metrics in terms of the original tensor or metric. * Added code to make the inverse of a Hermitian tensor also behave as a Hermitian tensor. 7/30/92 J. Lee * Added the CommutingFrame option for DefineBundle 7/13/92 J. Lee * Corrected sign bug in insertion of indices into RiemannTensor[g] 7/12/92 J. Lee * Corrected bug in insertion of indices into Sym[_] and Alt[_] 7/8/92 J. Lee * Added code to correctly handle Mma's builtin constants 7/7/92 J. Lee * Ricci Version 1.0 Beta 1 released This first beta release incorporated numerous changes from previous versions, formerly called DG. The most important were: * Change in syntax for DefineRelation and DefineRule: underscores no longer used in dummy index names. * Name changes: Tprod changed to TProd, Extdstar to ExtdStar, to be more consistent with Mathematica's and Ricci's naming conventions. * Delstar has been replaced by Div, and CovLaplacian has been replaced by Laplacian. * Many new functions and options added, such as ProductExpand, CovDExpand, SuperSimplify, BasisName, OrthonormalFrame, ParallelFrame.