caa a22 4500 605523347 CHVBK 20210128100749.0 cr unu---uuuuu 210128e20151201xx s 000 0 eng 10.1007/s10958-015-2606-z doi (NATIONALLICENCE)springer-10.1007/s10958-015-2606-z Gerasimova O. Moscow State University, Moscow, Russia aut Rolling Simplexes and Their Commensurability. II (A Lemma on the Directrix and Focus) [Elektronische Daten] [O. Gerasimova] The law of central-square dynamics x y z ″ = 4 π 2 k α x − a + β y − b + γ z − c + δ 2 x − a , y − b , z − c , $$ \left(x,y,z\right)^{{\prime\prime} }=\frac{4{\uppi}^2k}{{\left(\alpha \left(x-a\right)+\beta \left(y-b\right)+\gamma \left(z-c\right)+\delta \right)}^2}\left(x-a,y-b,z-c\right), $$ expressing the focusing of a plane wave at the point (a, b, c) is discussed and justified. Springer Science+Business Media New York, 2015 Journal of Mathematical Sciences Springer US; http://www.springer-ny.com 211/3(2015-12-01), 304-309 1072-3374 211:3<304 2015 211 10958 https://doi.org/10.1007/s10958-015-2606-z text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10958-015-2606-z text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Gerasimova O. Moscow State University, Moscow, Russia aut NATIONALLICENCE 773 0- Journal of Mathematical Sciences Springer US; http://www.springer-ny.com 211/3(2015-12-01), 304-309 1072-3374 211:3<304 2015 211 10958