define NR at first occurrence of numerical relativity

paper/paper.md

@@ -40,7 +40,7 @@ GRBoondi provides a unified interface for computing the evolution of any general
 
 # Statement of need
 
-In practice, any NR software library can be used to evolve generalized Proca theories. Prominent examples of NR codes encompass the extensive Einstein Toolkit [@EinsteinToolkit:2023_11] and its related Cactus framework [@Goodale:2002a], Kranc [@Kranc:web], LEAN [@Sperhake:2006cy], and Canuda [@Canuda:zenodo]. Other libraries worth mentioning are the non-public BAM [@Bruegmann:2006ulg], AMSS-NCKU [@Galaviz:2010mx], PAMR [@East:2011aa] and HAD [@Neilsen:2007ua]. The non-exhaustive list can be expanded with SPeC [@Pfeiffer:2002wt], which is a pseudo-spectral code that uses generalized harmonic coordinates. Similarly, SpECTRE [@deppe_nils_2021_4734670;@Kidder:2016hev;@Cao:2018vhw] uses the Galerkin methods. NRPy [@Ruchlin:2017com] is a Python library that aims for use on non-high performance computing clusters. There are also cosmological simulation codes like CosmoGRaPH [@Mertens:2015ttp] and GRAMSES [@Barrera-Hinojosa:2019mzo]. Simflowny [@Palenzuela:2018sly] is a magneto-hydrodynamic simulation software. GR-Athena++ [@Daszuta:2021ecf] uses the oct-tree AMR for maximum scaling. ExaGRyPE is a numerical relativity (NR) program leveraging the ExaHyPRE PDE solver [@zhang2024exagrypenumericalgeneralrelativity]. GRDzhadzha [@Aurrekoetxea2024] is another fixed background code, based off the GRChombo [@Andrade2021] framework, which GRBoondi utilizes.
+In practice, any numerical relativity (NR) software library can be used to evolve generalized Proca theories. Prominent examples of NR codes encompass the extensive Einstein Toolkit [@EinsteinToolkit:2023_11] and its related Cactus framework [@Goodale:2002a], Kranc [@Kranc:web], LEAN [@Sperhake:2006cy], and Canuda [@Canuda:zenodo]. Other libraries worth mentioning are the non-public BAM [@Bruegmann:2006ulg], AMSS-NCKU [@Galaviz:2010mx], PAMR [@East:2011aa] and HAD [@Neilsen:2007ua]. The non-exhaustive list can be expanded with SPeC [@Pfeiffer:2002wt], which is a pseudo-spectral code that uses generalized harmonic coordinates. Similarly, SpECTRE [@deppe_nils_2021_4734670;@Kidder:2016hev;@Cao:2018vhw] uses the Galerkin methods. NRPy [@Ruchlin:2017com] is a Python library that aims for use on non-high performance computing clusters. There are also cosmological simulation codes like CosmoGRaPH [@Mertens:2015ttp] and GRAMSES [@Barrera-Hinojosa:2019mzo]. Simflowny [@Palenzuela:2018sly] is a magneto-hydrodynamic simulation software. GR-Athena++ [@Daszuta:2021ecf] uses the oct-tree AMR for maximum scaling. ExaGRyPE is a NR program leveraging the ExaHyPRE PDE solver [@zhang2024exagrypenumericalgeneralrelativity]. GRDzhadzha [@Aurrekoetxea2024] is another fixed background code, based off the GRChombo [@Andrade2021] framework, which GRBoondi utilizes.
 
 This extensive list underscores the abundance of NR libraries at one's disposal. However, none of them provide a tailored unified interface for studying the vast landscape of gravity theories, like generalized Proca. Using any of the numerous frameworks requires significant work in order to evolve even a single generalized Proca theory. GRBoondi tackles this problem by providing a collection of specialized tools for computing the generalized Proca equations, relying on existing tools which allows for rapid updating and debugging. On top of this, GRBoondi offers catered plotting routines for viewing data, leveraging the highly parallelizable VisIt [@visit_dav] analysis tool. In addition, since the metric variables and their derivatives are computed exactly at each grid point, the adaptability of the AMR grid can be focused solely on the matter variables.