Zobrazeno 1 - 10
of 54
pro vyhledávání: '"Tsvetan Hristov"'
Publikováno v:
Mathematics, Vol 11, Iss 10, p 2238 (2023)
Bulgaria has the lowest COVID-19 vaccination rate in the European Union and the second-highest COVID-19 mortality rate in the world. That is why we think it is important better to understand the reason for this situation and to analyse the developmen
Externí odkaz:
https://doaj.org/article/410d2ff7793f4214b80a2110b57f7569
Publikováno v:
Mathematics, Vol 10, Iss 15, p 2570 (2022)
Data from the World Health Organization indicate that Bulgaria has the second-highest COVID-19 mortality rate in the world and the lowest vaccination rate in the European Union. In this context, to find the crucial epidemiological parameters that cha
Externí odkaz:
https://doaj.org/article/f0e62472e2fe4a38853ece5a46d8320d
Publikováno v:
Advances in Mathematical Physics, Vol 2017 (2017)
We study a boundary value problem for (3 + 1)-D weakly hyperbolic equations of Keldysh type (problem PK). The Keldysh-type equations are known in some specific applications in plasma physics, optics, and analysis on projective spaces. Problem PK is n
Externí odkaz:
https://doaj.org/article/49bc1b3cff8344fa8419131ca4da94c0
Publikováno v:
“TOPICAL ISSUES OF THERMOPHYSICS, ENERGETICS AND HYDROGASDYNAMICS IN THE ARCTIC CONDITIONS”: Dedicated to the 85th Birthday Anniversary of Professor E. A. Bondarev.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::a17f1ec4f3255d3087422e73851832ad
https://doi.org/10.1063/5.0106519
https://doi.org/10.1063/5.0106519
Publikováno v:
“TOPICAL ISSUES OF THERMOPHYSICS, ENERGETICS AND HYDROGASDYNAMICS IN THE ARCTIC CONDITIONS”: Dedicated to the 85th Birthday Anniversary of Professor E. A. Bondarev.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::9bb1455c3585182a4b5032231fbe816f
https://doi.org/10.1063/5.0106518
https://doi.org/10.1063/5.0106518
Publikováno v:
Mathematics; Volume 10; Issue 15; Pages: 2570
Data from the World Health Organization indicate that Bulgaria has the second-highest COVID-19 mortality rate in the world and the lowest vaccination rate in the European Union. In this context, to find the crucial epidemiological parameters that cha
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::a12213e7dab27c1b2006cfe549e495a1
https://doi.org/10.3390/math10152570
https://doi.org/10.3390/math10152570
Publikováno v:
THERMOPHYSICAL BASIS OF ENERGY TECHNOLOGIES (TBET 2020).
In this paper we explore a time-depended SEIR model, in which the dynamics of the infection in four groups from a selected target group (population), divided according to the infection, are modeled by a system of nonlinear ordinary differential equat
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::2e41a5c8f93191076369445cef0d1bc8
https://doi.org/10.1063/5.0041868
https://doi.org/10.1063/5.0041868
Autor:
Tsvetan Hristov
Publikováno v:
AIP Conference Proceedings.
The three-dimensional Protter-Morawetz problem for weakly hyperbolic equations of Keldysh type involving lower order terms is studied. Similar problem for Tricomi-type equations was proposed by M. Protter in connection with the Guderley-Morawetz plan
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::3b830617668f1b522efb09b600d14904
https://doi.org/10.1063/1.5082097
https://doi.org/10.1063/1.5082097
Publikováno v:
AIP Conference Proceedings.
This paper deals with Protter problems for Keldysh type equations in ℝ4. Originally such type problems are formulated by M. Protter for equations of Tricomi type. Now it is well known that Protter problems for mixed type equations of the first kind
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::5f3d1386f0f598d3a9109c9919777118
https://doi.org/10.1063/1.4968460
https://doi.org/10.1063/1.4968460
Publikováno v:
Siberian Advances in Mathematics. 21:262-273
Some three-dimensional (3D) problems for mixed type equations of first and second kind are studied. For equation of Tricomi type, they are 3D analogs of the Darboux (or Cauchy-Goursat) plane problem. Such type problems for a class of hyperbolic and w
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::08b121f05af8f5f409bbc84685ea3635
https://doi.org/10.3103/s1055134411040043
https://doi.org/10.3103/s1055134411040043