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Related papers: Olmec mirrors: an example of archaeological Americ…

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The advent of extremely large telescopes will bring unprecedented light-collecting power and spatial resolution, but it will also lead to a significant increase in the size and complexity of focal-plane instruments. The use of freeform…

We study some basic properties and examples of Hermitian metrics on complex manifolds whose traces of the curvature of the Chern connection are proportional to the metric itself.

Differential Geometry · Mathematics 2020-07-22 Daniele Angella , Simone Calamai , Cristiano Spotti

We address the possibility that intelligent civilisations that destroy themselves could present signatures observable by humanity. Placing limits on the number of self-destroyed civilisations in the Milky Way has strong implications for the…

Earth and Planetary Astrophysics · Physics 2020-12-16 Adam Stevens , Duncan Forgan , Jack O'Malley-James

In this short note, we simply collect some known results about representing algebraic cycles by various kind of "nice" (e.g. smooth, local complete intersection, products of local complete intersection) algebraic cycles, up to rational…

Algebraic Geometry · Mathematics 2016-12-15 Marco Maggesi , Gabriele Vezzosi

This is the first of a series of papers in which we initiate and develop the theory of reflection monoids, motivated by the theory of reflection groups. The main results identify a number of important inverse semigroups as reflection…

Group Theory · Mathematics 2007-11-07 Brent Everitt , John Fountain

The paper surveys the history and state-of-the-art of the study of Jordan homomorphisms.

Rings and Algebras · Mathematics 2025-10-21 Matej Brešar , Efim Zelmanov

Mirrors are a subset of optical components essential for the success of current and future space missions. Most of the telescopes for space programs ranging from Earth Observation to Astrophysics and covering all the electromagnetic…

Instrumentation and Methods for Astrophysics · Physics 2020-10-02 D. Garoli , L. V. Rodriguez De Marcos , J. I. Larruquert , A. J. Corso , R. Proietti Zaccaria , M. G. Pelizzo

This paper agrees basically with the talk of the author at the workshop "Homological Mirror Symmetry and Applications", Institute for Advanced Study, Princeton, March 2007.

High Energy Physics - Theory · Physics 2007-06-27 Karl-Georg Schlesinger

The lunar surface is a compelling location for large, distributed optical facilities, with significant advantages over orbital facilities for high spatial resolution astrophysics. The serious development of mission concepts is timely…

Astronomical observations were used as a marker for time and the Calendar from ancient times. A more subtle calibration of epochs is thrown up by an observation of the position of the solstices and equinoxes, because these points shift in…

General Physics · Physics 2011-02-04 Burra G. Sidharth

The impact of autonomous systems on astrophysics can be just as revolutionary as in our daily lives. This paper includes the following so that the astrophysics community can realize the benefits of autonomous systems: description of…

Instrumentation and Methods for Astrophysics · Physics 2020-09-17 Rashied Amini , Steve Chien , Lorraine Fesq , Jeremy Frank , Ksenia Kolcio , Bertrand Mennsesson , Sara Seager , Rachel Street

The mirror of a toric orbifold is an affine curve called the mirror curve. In this paper, firstly, we recall the basic tools in tropical geometry and give a definition of the mirror curve. Then we calculate the tropical spine of the mirror…

Algebraic Geometry · Mathematics 2022-12-13 Zhaoxing Gu

X-ray mirror fabrication for astronomy is challenging; this is due to the Wolter I optical geometry and the tight tolerances on roughness and form error to enable accurate and efficient X-ray reflection. The performance of an X-ray mirror,…

Instrumentation and Methods for Astrophysics · Physics 2023-04-05 Carolyn Atkins

It is often stated that cosmology is an extreme form of archeology that deals with aeons of time extending back to thousands of millions of years. One talks, for instance, of relics of the early Universe, and phases in the history of the…

History and Philosophy of Physics · Physics 2011-12-13 Orfeu Bertolami

ECM survey article discussing the structure of subsets of Abelian groups which behave `a bit like' cosets (of subgroups).

Classical Analysis and ODEs · Mathematics 2018-11-05 Tom Sanders

There has been a long standing debate about the existence of maya constellations, but there are several sources of evidences that favour this hypothesis: mural paintings, stelae and codex. In this work, we have recovered and compiled…

History and Philosophy of Physics · Physics 2021-08-22 Eduardo Rodas-Quito , Javier Mejuto

Glints of light from specular reflection of the Sun are a technosignature of artificial satellites. If extraterrestrial intelligences have left artifacts in the Solar System, these may include flat mirror-like surfaces that also can glint.…

Earth and Planetary Astrophysics · Physics 2020-02-04 Brian C. Lacki

This is a brief rebuttal to arXiv:1502.03821, which claims to provide the first observational proof of dark matter interior to the solar circle. We point out that this result is not new, and can be traced back at least a quarter century.

We define the concept of self-similarity of an object by considering endomorphisms of the object as `similarity' maps. A variety of interesting examples of self-similar objects in geometry, algebra and arithmetic are introduced.…

Number Theory · Mathematics 2015-06-05 Arash Rastegar

The mirrors of imaging atmospheric Cherenkov telescopes are different from those of conventional astronomical telescopes in several ways, not least in that they are exposed to the elements. One of the issues which may arise is condensation…

Instrumentation and Methods for Astrophysics · Physics 2019-08-15 P. M. Chadwick , S. A. Cleaver , M. Dyrda , A. Förster , J. Michalowski , J. Niemiec , C. Schultz , M. Stodulski