Hi, Le jeudi 18 août 2016 07:59:15 UTC+2, Nils Bruin a écrit : > > > The situation for topological manifolds is slightly different, because > expressions there live in the context of a chart, where a specific > correspondence between variable name and parameter position has been > imposed. That makes it plausible that in the context of charts, one can get > away with possible ambiguities a little easier. >
Yes indeed! Actually in the manifolds code, ExpressionNice is used to display the expression of functions M --> K (M = the manifold, K = the base field) in a specified coordinate chart. There is then no ambiguity regarding the variables, which are the coordinates. Examples of use are [1] http://nbviewer.jupyter.org/github/egourgoulhon/BHLectures/blob/master/sage/Kottler_solution.ipynb [2] http://nbviewer.jupyter.org/github/sagemanifolds/SageManifolds/blob/master/Worksheets/v0.9/SM_Tolman-Oppenheimer-Volkoff_equations.ipynb In [1], note the rendering of the system of equations in Out[9] -- Out[12], which is in textbook style. Same thing for Out[32] in [2]. > That said, I find it hard to not consider the example (*) an outright bug. > It was exhibited to show clearly the limitations of ExpressionNice. This is why in SageMath 7.3 ExpressionNice lies in src/sage/manifolds/utilities.py and not in src/sage/symbolic. Best wishes, Eric. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
