** Spinors**: Spinor calculus in General Relativity

**Authors:**Alfonso García-Parrado and José M. Martín-García © 2007-2015 under GPL.

**Article:**A. García-Parrado, J. M. Martín-García, Comp. Phys. Comm. 183 (2012) 2214-2225, arXiv: 1110.2662 [gr-qc].

# Introduction

*Spinors* is a package for spinor calculus in four dimensionali
Lorentzian geometry. Some relevant features of the package are:

- Inclusion of all the quantities which are typical of the spinor calculus (antisymmetric metric, curvature spinors, 2-index covariant derivatives and more).
- Efficient tools to transform tensor into spinor expressions and back.
- Simplification of spinor expressions taking into account the specific conventions of the spinor calculus.
- Step by step derivation of all the Newman-Penrose and
Geroch-Held-Penrose (GHP) equations
using a combination of
*Spinors*and other*xAct*packages.

See Spinors.History

# Download and installation

Current version: 1.0.6 (as of 28 September 2014). It is recommended to
download the main *xAct* bundle, but
you can also download the different files separately:

- Spinors.nb: source file.
- Spinors.m: package file. This file is automatically generated by Mathematica when Spinors.nb is saved. This is the only essential file.
- SpinorsDoc.nb: main documentation file.
- PublicNPGHP.nb: explicit, step-by-step construction of the Newman-Penrose and Geroch-Held-Penrose formalisms, using the
*Spinors*package. - SpinorsCPCNotebook.nb: examples in the article above.
- General Public License.

See the file Spinors.readme and the Installation notes.

Previous versions:

- Spinors_1.0.5 (as of 15 February 2014).
- Spinors_1.0.4 (as of 27 January 2013).
- Spinors_1.0.3 (as of 5 May 2012).
- Spinors_1.0.2 (as of 25 October 2011).
- Spinors_1.0.1 (as of 17 April 2011).
- Spinors_1.0.0 (as of 30 September 2010).
- Spinors_0.9.2 (as of 10 January 2010).
- Spinors_0.9.1 (as of 1 December 2008).
- Spinors_0.9.0 (as of 11 August 2008).