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Suppose we concatenate two directed graphs, each isomorphic to a $d$ dimensional butterfly (but not necessarily identical to each other). Select any set of $2^k$ input and $2^k$ output nodes on the resulting graph. Then there exist node…

Data Structures and Algorithms · Computer Science 2014-01-29 William F. Bradley

Butterflies are the smallest non-trivial subgraph in bipartite graphs, and therefore having efficient computations for analyzing them is crucial to improving the quality of certain applications on bipartite graphs. In this paper, we design…

Distributed, Parallel, and Cluster Computing · Computer Science 2020-06-18 Jessica Shi , Julian Shun

Bipartite graphs characterize relationships between two different sets of entities, like actor-movie, user-item, and author-paper. The butterfly, a 4-vertices 4-edges (2,2)-biclique, is the simplest cohesive motif in a bipartite graph and…

Data Structures and Algorithms · Computer Science 2026-04-21 Xinwei Cai , Xiangyu Ke , Kai Wang , Lu Chen , Tianming Zhang , Qing Liu , Yunjun Gao

We introduce a fast algorithm for computing sparse Fourier transforms supported on smooth curves or surfaces. This problem appear naturally in several important problems in wave scattering and reflection seismology. The main observation is…

Numerical Analysis · Mathematics 2008-01-11 Lexing Ying

We revisit the problem of self-similar properties of the Hofstadter butterfly spectrum, focusing on spectral as well as topological characteristics. In our studies involving any value of magnetic flux and arbitrary flux interval, we single…

Disordered Systems and Neural Networks · Physics 2014-12-16 Indubala Satija

The Chern numbers for Hofstadter models with rational flux 2*pi*p/q are partially determined by a Diophantine equation. A Mod q ambiguity remains. The resolution of this ambiguity is only known for the rectangular lattice with nearest…

Mathematical Physics · Physics 2014-04-24 J. E. Avron , O. Kenneth , G. Yehoshua

Recently, a new structure called butterfly introduced by Perrin et at. is attractive for that it has very good cryptographic properties: the differential uniformity is at most equal to 4 and algebraic degree is also very high when exponent…

Information Theory · Computer Science 2023-05-11 Shihui Fu , Xiutao Feng

Community search aims at finding densely connected subgraphs for query vertices in a graph. While this task has been studied widely in the literature, most of the existing works only focus on finding homogeneous communities rather than…

Social and Information Networks · Computer Science 2021-05-21 Zheng Dong , Xin Huang , Guorui Yuan , Hengshu Zhu , Hui Xiong

We experimentally probe complex bio-photonic architecture of microstructures on the transparent insect wings by a simple, non-invasive, real time optical technique. A stable and reproducible far-field diffraction pattern in transmission was…

The Hofstadter butterfly spectral patterns of lattice electrons in an external magnetic field yield some of the most beguiling images in physics. Here we explore the magneto-electronic spectra of systems with moire spatial patterns,…

Mesoscale and Nanoscale Physics · Physics 2015-05-27 R. Bistritzer , A. H. MacDonald

Bipartite graphs offer a powerful framework for modeling complex relationships between two distinct types of vertices, incorporating probabilistic, temporal, and rating-based information. While the research community has extensively…

Social and Information Networks · Computer Science 2023-08-17 Apurba Das , Aman Abidi , Ajinkya Shingane , Mekala Kiran

Temporal bipartite graphs are widely used to denote time-evolving relationships between two disjoint sets of nodes, such as customer-product interactions in E-commerce and user-group memberships in social networks. Temporal butterflies,…

Social and Information Networks · Computer Science 2023-10-19 Jiaxi Pu , Yanhao Wang , Yuchen Li , Xuan Zhou

We present an algorithm for reliably and systematically proving the existence of spectral gaps in Hamiltonians with quasicrystalline order, based on numerical calculations on finite domains. We apply this algorithm to prove that the…

Quantum Physics · Physics 2022-10-25 Paul Hege , Massimo Moscolari , Stefan Teufel

This paper establishes several sharp spectral results for analytic quasiperiodic Schrodinger operators. Key contributions include: (1) exact exponential decay rates for spectral gaps of the almost Mathieu operator, addressing a question…

Dynamical Systems · Mathematics 2025-11-25 Lingrui Ge , Jiangong You , Qi Zhou

We calculate the electronic structure in quasiperiodic double-moir\'e systems of graphene sandwiched by hexagonal boron nitride, and identify the topological invariants of energy gaps. We find that the electronic spectrum contains a number…

Mesoscale and Nanoscale Physics · Physics 2021-08-04 Hiroki Oka , Mikito Koshino

The energy spectrum of a tight-binding Hamiltonian is studied for the two-dimensional quasiperiodic Rauzy tiling in a perpendicular magnetic field. This spectrum known as a Hofstadter butterfly displays a very rich pattern of bulk gaps that…

Mesoscale and Nanoscale Physics · Physics 2016-11-30 J. -N Fuchs , J. Vidal

Celebrating its golden jubilee, the Hofstadter butterfly fractal emerges as a remarkable fusion of art and science. This iconic X shaped fractal captivates physicists, mathematicians, and enthusiasts alike by elegantly illustrating the…

Mesoscale and Nanoscale Physics · Physics 2025-07-21 Indubala Satija

The hierarchical structure of the butterfly fractal -- the Hofstader butterfly, is found to be described by an octonary tree. In this framework of building the butterfly graph, every iteration generates sextuplets of butterflies, each with…

General Mathematics · Mathematics 2024-06-04 Indubala I Satija

We prove a uniform spectral gap for complex transfer operators near the critical line associated to overlapping $C^2$ iterated function systems on the real line satisfying a Uniform Non-Integrability (UNI) condition. Our work extends that…

Dynamical Systems · Mathematics 2023-06-05 Simon Baker , Tuomas Sahlsten

Bipartite graphs are ubiquitous in many domains, e.g., e-commerce platforms, social networks, and academia, by modeling interactions between distinct entity sets. Within these graphs, the butterfly motif, a complete 2*2 biclique, represents…

Social and Information Networks · Computer Science 2025-01-14 Qiuyang Mang , Jingbang Chen , Hangrui Zhou , Yu Gao , Yingli Zhou , Qingyu Shi , Richard Peng , Yixiang Fang , Chenhao Ma