Daniel Volinski

I downloaded the paper Algebraic computing and the Newman–Penrose formalism by Esteban and Ramos, referenced also in the REDUCE bibliography page: https://reduce-algebra.sourceforge.io/bibliography.php under letter E. This PDF contains a huge REDUCE file which has become a nightmare to convert to text: "The algorithm's input is the null tetrads. Then, a straightforward procedure is followed. We illustrate the procedure with the following program which is self-explanatory". Does anyone have this file...

Hi Arthur, Thank you for your response! Daniel Volinski

Hi Eberhard, Yes, it works fine. I put both procedures after loading EXCALC. I run Example 13, and I get both the frame and the coframe when issuing the command "displayframe". Moreover, the commutator of the dual frame displays results correctly as the documentation of this example. Thank you. Daniel Volinski

Thank you Arthur for your response. Where exactly can I find documentation on symbolic mode function remflag and others like it, that I can use in REDUCE but do not appear in the REDUCE documentation? Daniel Volinski

Hi Eberhard, I was not able to find any mention of the command "remflag" in the REDUCE User's manual (June 23, 2025), that you use in your script: "remflag('(u a),'covariant);" Daniel Volinski

Example 13 of EXCALC manual

Hi Eberhard, Thank you for the answer and sorry for my confusion. Daniel Volinski

EXCALC geodesic equations