Manos Kamarianakis, Antonis Protopsaltis, George Papagiannakis
{"title":"One algebra for all: geometric algebra methods for neurosymbolic XR scene authoring, animation and neural rendering.","authors":"Manos Kamarianakis, Antonis Protopsaltis, George Papagiannakis","doi":"10.1098/rsta.2025.0109","DOIUrl":"10.1098/rsta.2025.0109","url":null,"abstract":"<p><p>This position paper delves into the transformative role of geometric algebra (GA) in advancing specific areas of computer graphics (CG) and extended reality (XR), particularly in character animation, rendering, rigging, neural rendering and generative artificial intelligence (AI)-driven scene editing. Common CG algorithms require handling rotations, translations and dilations (uniform scalings) in operations such as object rendering, rigged model animation, soft-body deformation and XR simulations. Traditional representation forms-such as matrices, quaternions and vectors-often introduce limitations in precision and performance. Recent breakthroughs in the use of GA suggest it can significantly enhance these processes by encapsulating geometric forms and transformations into uniform algebraic expressions, which maintain critical geometric properties throughout multi-step transformations. Furthermore, we explore how GA can serve as a unifying mathematical substrate for neurosymbolic XR scene authoring, bridging learned neural representations and explicit geometric reasoning. This paper outlines how GA-based approaches can improve the fidelity of rigged character animations, enhance soft-body simulations, streamline real-time rendering and optimize neural and generative AI scene editing. GA offers a coherent and efficient framework for these processes, resulting in superior visual outcomes and computational efficiency, particularly in XR environments. This article is part of the theme issue 'Modern applications of geometric algebra'.</p>","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"384 2326","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148723645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Splossoms: blossoming polynomials on the sphere via geometric algebra.","authors":"Alyn Rockwood","doi":"10.1098/rsta.2025.0106","DOIUrl":"10.1098/rsta.2025.0106","url":null,"abstract":"<p><p>We introduce splossoms, the spherical analogue of polynomial blossoms, extending Ramshaw's theory of blossoming into spherical geometry. We note that the classical blossom axioms require spherical reinterpretation: strict symmetry does not hold on S2, and we identify the appropriate spherical analogues that the splossom satisfies. Splossoms provide a structured approach to designing spherical curves, generalizing Shoemake's SLERP interpolation. In addition, we define spolynomials, iterated spherical interpolants that mirror polynomial structures such as Bézier and B-spline forms, and we study their continuity. Potential applications include robotics, CNC milling, virtual/augmented reality and computer animation, where orientation curves on spheres are central. The splossom is naturally expressed in the framework of geometric algebra (GA), where rotors and spinors generalize quaternionic rotation and make spherical curve construction both simpler and more powerful. We argue that while splines on Lie groups and algebras are of general mathematical interest, GA provides a direct and computationally efficient setting for implementation. This article is part of the theme issue 'Modern applications of geometric algebra'.</p>","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"384 2326","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148725433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Geometric algebra integral transforms and their applications.","authors":"Eckhard Hitzer","doi":"10.1098/rsta.2025.0108","DOIUrl":"10.1098/rsta.2025.0108","url":null,"abstract":"<p><p>In geometric algebra (GA), real and complex integral transforms (Fourier transforms, linear canonical transforms (LCTs), wavelets, fractional Fourier transforms, special affine Fourier transforms, etc.) can be generalized to holistic higher-dimensional quaternionic, octonionic and Clifford GA versions. This review introduces the foundations of these generalizations, provides representative examples of these new types of transforms and refers to some of their applications in mathematics, physics and engineering. This article is part of the theme issue 'Modern applications of geometric algebra'.</p>","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"384 2326","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148727352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The role of quantum entanglement in three players cooperative game.","authors":"Jaroslav Hrdina","doi":"10.1098/rsta.2025.0111","DOIUrl":"10.1098/rsta.2025.0111","url":null,"abstract":"<p><p>This work explores the application of quantum entanglement to the analysis of cooperative three-player games. The interactions between players influence their behaviour and the overall outcomes of the transferable utility (TU) cooperative game. The mathematical framework employed is the quantum register algebra (QRA), which algebraizes the Dirac formalism. By using QRA, we can simulate the game and explore how different levels of entanglement impact players. This article is part of the theme issue 'Modern applications of geometric algebra'.</p>","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"384 2326","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148722837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Null geometric algebra with geometric interpretation.","authors":"Hongbo Li","doi":"10.1098/rsta.2025.0096","DOIUrl":"10.1098/rsta.2025.0096","url":null,"abstract":"<p><p>Null geometric algebra (NGA) refers to a basis-free version of Clifford algebra where the base vector space is spanned by vectors whose inner product with itself equals zero. It provides powerful tools for manipulating expressions in conformal geometric algebra (CGA) when making symbolic reasoning in classical geometry. This paper develops several new techniques in NGA and uses them to explore the geometric interpretations of basic algebraic objects in NGA-null monomials, their scalar parts and pseudo-scalar parts, centred null binomials-and illustrates how these objects are used in making geometric reasoning for problems in classical geometry. This article is part of the theme issue 'Modern applications of geometric algebra'.</p>","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"384 2326","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148725892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Generative geospatial modelling with geometric algebra.","authors":"Zhaoyuan Yu, Jian Wang, Zengjie Wang, Yi Liu, Dmitry Shirokov, Dietmar Hildenbrand, Linwang Yuan","doi":"10.1098/rsta.2025.0103","DOIUrl":"10.1098/rsta.2025.0103","url":null,"abstract":"<p><p>The integration of data-driven and knowledge-driven approaches in generative geospatial modelling (GGM) is often hindered by their mathematical incompatibilities. Here, we propose a geometric algebra (GA)-based framework that employs a unified multi-vector representation to fuse heterogeneous data and diverse knowledge. The framework facilitates structured reasoning and hypothesis generation through a task-adaptable, five-stage cycle: representation, reasoning, generation, synthesis and computation. We illustrate this design through three case studies covering constrained trajectory reconstruction, typhoon intensity prediction and large language model-based GA code generation, which instantiate different components and implementation levels of the proposed framework. By offering a cohesive mathematical perspective, our work provides a conceptual and methodological framework for interpretable and constraint-aware GGM. This article is part of the theme issue 'Modern applications of geometric algebra'.</p>","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"384 2326","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148723314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Clifford algebra approach to bosonic strings with fermionic boundaries.","authors":"Andrew Hamilton, Tyler McMaken","doi":"10.1098/rsta.2025.0095","DOIUrl":"10.1098/rsta.2025.0095","url":null,"abstract":"<p><p>The Brauer-Weyl theorem (Brauer, Weyl. 1935 Am. J. Maths. 57, 425-449. (doi:10.2307/2371218)) states that the algebra of tensor products of spinors is isomorphic to the Clifford (geometric) algebra, in any number of space-time dimensions. The algebraic relation between fermions and bosons seen in the standard model agrees with the Brauer-Weyl theorem, but not with supersymmetry. It is commonly argued that string theory requires supersymmetry, on the grounds that non-supersymmetric bosonic string theory (i) does not admit fermions, and (ii) has an unstable tachyonic ground state. This paper rebuts those standard objections, pointing out that bosonic string theory admits fermions lying on a D-brane boundary of open strings, and that the open-string tachyon has all the properties of a Higgs field. The original 1970's formulation of bosonic string theory, re-envisaged as a theory of all the forces, not just the strong force, fits the standard model beautifully. This article is part of the theme issue 'Modern applications of geometric algebra'.</p>","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"384 2326","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148726653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A geometric algebra approach to coincidence site lattices.","authors":"Marco A Rodríguez-Andrade, José L Aragón","doi":"10.1098/rsta.2025.0097","DOIUrl":"10.1098/rsta.2025.0097","url":null,"abstract":"<p><p>When a lattice in Rn is superimposed on a rotated copy with coincident origins, coincidence points may arise for specific rotations, forming a coincidence site lattice (CSL). In crystallography, particularly in two and three dimensions, CSL theory is fundamental for describing low-energy grain boundaries. Geometric (Clifford) algebra provides a natural framework for this problem, as orthogonal transformations can be expressed as products of reflections. This article presents a unified account of the geometric algebra approach to coincidence isometries, including a Cartan-type decomposition of coincidence rotations for hypercubic lattices Zn. We then summarize the analytical characterization of coincidence rotations, indices and bases for planar hexagonal lattices. The main new result is a rigorous extension of these results to honeycomb structures, such as graphene, which are periodic but not Bravais lattices. We prove that the coincidence structure of two rotated honeycombs is completely determined by the coincidence lattice of their associated hexagonal Bravais lattices. As an application, structures near the first magic angle in twisted bilayer graphene are analysed, yielding quantitative agreement with experimentally observed Moiré lattice parameters. This article is part of the theme issue 'Modern applications of geometric algebra'.</p>","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"384 2326","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148722263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Closed-form solutions for rigid transformations between heterogeneous groups of noisy geometric primitives.","authors":"Hugo Hadfield","doi":"10.1098/rsta.2025.0110","DOIUrl":"10.1098/rsta.2025.0110","url":null,"abstract":"<p><p>Computing the transformation between noisy collections of geometric primitives is a classic problem in three-dimensional computer vision and geometric computing. In this paper, we consider minimum sets of noisy objects and provide closed-form formulae to compute the Euclidean transformation that best transforms from one of these sets to another set. We enumerate these for all primitive object groups that appear in common three-dimensional computer vision problems and describe example applications. This article is part of the theme issue 'Modern applications of geometric algebra'.</p>","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"384 2326","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148726823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Oliver Rettig, Jaroslav Hrdina, Dietmar Hildenbrand
{"title":"Geometric algebra: an overview about different implementation representations and memory requirements.","authors":"Oliver Rettig, Jaroslav Hrdina, Dietmar Hildenbrand","doi":"10.1098/rsta.2025.0104","DOIUrl":"10.1098/rsta.2025.0104","url":null,"abstract":"<p><p>Several implementations of geometric algebra are available, and many have been approved in the past and can be found in various software codes. For low-dimensional algebras, representations as a sum of basis blades are typically the most suitable. However, isomorphic or irreducible matrix representations are also options. Techniques such as compression on a per-coordinate, per-grade or per-group basis, as well as the use of sparse matrices, can help reduce memory consumption. In the case of high-dimensional algebras, factorized representations can significantly decrease the memory needed for blades and versors, reducing it to O(n2), as opposed to the O(2n) required to represent a complete basis of blades. This is particularly relevant in the context of quantum computing, where high dimensionality and memory usage are increasingly important considerations. This paper reviews various implementation strategies, classifies the corresponding software tools and libraries and highlights recent advancements aimed at reducing memory consumption within the tool Gaalop. This article is part of the theme issue 'Modern applications of geometric algebra'.</p>","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"384 2326","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148724952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}