Related papers: 25 years ago: the official farewell to the meter
Computing the Fr\'{e}chet distance for surfaces is a surprisingly hard problem and the only known algorithm is limited to computing it between flat surfaces. We adapt this algorithm to create one for computing the Fr\'{e}chet distance for a…
The annual meeting of the European Astronomical Society took place in Lyon, France, in 2019, but in 2020 it was held online only due the COVID-19 pandemic. The carbon footprint of the virtual meeting was roughly 3,000 times smaller than the…
The moon is receding from earth at an average rate of 3.8 cm/yr [6][7][9][12].This anomaly cannot be attributed to the well-known tidal exchange of angular momentum between earth and moon [8]. A secular change in the astronomical unit AU is…
In January of 1985, more than 40 years ago, a group of astronomers met with NASA officials to map out the future of NASA space astronomy. Their efforts led to the Great Observatories program, linking four powerful space telescopes to study…
I discuss an apparently simple ballistics problem: the time it takes an object to fall a small vertical distance near the surface of the Earth. It turns out to be not so simple; I spend a great deal of time on the quantitative assessment of…
Distance measures are indispensable tools in quantum information processing and quantum computing. This since they can be used to quantify to what extent information is preserved, or altered, by quantum processes. In this paper we propose a…
We propose a covariant and geometric framework to introduce space distances as they are used by astronomers. In particular, we extend the definition of space distances from the one used between events to non-test-bodies with horizons and…
This paper has been withdrawn by the author. The metrics presented are known since 1969 (and are referred to as C-metrics)
The most recent cosmological observations indicate that the present universe is flat and vacuum dominated. In such a universe, the distance measurements are always difficult and involve numerical computations. In this paper, it is shown…
This work deals with the comparison of different parameters (French/IMCCE and US/JPL ephemerides) used to calculate the extension of the umbral shadow and the location of the centre line in the total solar eclipse that took place on March,…
This is a survey paper on several aspects of differential geometry for the last 30 years, especially in those areas related to non-linear analysis. It grew from a talk I gave on the occasion of seventieth anniversary of Chinese Mathematical…
The Michelson Doppler Imager (MDI) aboard the Solar and Heliospheric Observatory observed the transits of Mercury on 2003 May 7 and 2006 November 8. Contact times between Mercury and the solar limb have been used since the 17th century to…
The paper has been withdrawn.
This is a survey on special metrics. We shall present some results and open questions on special metrics mainly appeared in the last 10 years
On April 22 2015, Murray Marshall was invited by Igor Klep and Victor Vinnikov to talk in the special session on "Operator Theory, Real Algebraic Geometry, and Moment Problems" that they co-organised for IWOTA 2015 in Tbilisi, Georgia, July…
This is an English translation of the obituary notice by Beno Eckmann, appearing in Elemente der Mathematik 47.3 (1992) 118--122 (in German).
We introduce a new distance-preserving compact representation of multi-dimensional point-sets. Given $n$ points in a $d$-dimensional space where each coordinate is represented using $B$ bits (i.e., $dB$ bits per point), it produces a…
As is well known, classical systems approximate quantum ones -- but how well? We introduce a definition of a "distance" on classical and quantum phase spaces that offers a measure of their separation. Such a distance scale provides a means…
The goal of this introduction to symmetries is to present some general ideas, to outline the fundamental concepts and results of the subject and to situate a bit the following lectures of this school. [These notes represent the write-up of…
Given a fixed closed manifold M, we exhibit an explicit formula for the distance function of the canonical L^2 Riemannian metric on the manifold of all smooth Riemannian metrics on M. Additionally, we examine the (metric) completion of the…