{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,27]],"date-time":"2025-10-27T05:05:56Z","timestamp":1761541556039,"version":"build-2065373602"},"reference-count":28,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2020,8,1]],"date-time":"2020-08-01T00:00:00Z","timestamp":1596240000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>We investigate the dynamics of dust matter with bulk viscosity effects. We explored the analogy dynamical problem to Chaplygin gas. Due to this analogy we give exact solutions for the FRW cosmology with viscosity coefficient parameterized by the Belinskii\u2013Khalatnikov power law dependence with respect to energy density. These exact solutions are given in the form of hypergeometrical functions. We proved simple theorem which illustrated as viscosity effects can solved the initial singularity problem present in standard cosmological model.<\/jats:p>","DOI":"10.3390\/sym12081269","type":"journal-article","created":{"date-parts":[[2020,8,3]],"date-time":"2020-08-03T07:45:57Z","timestamp":1596440757000},"page":"1269","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Viscous Matter in FRW Cosmology"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1067-4845","authenticated-orcid":false,"given":"Marek","family":"Szyd\u0142owski","sequence":"first","affiliation":[{"name":"Astronomical Observatory, Jagiellonian University, Orla 171, 30-244 Krak\u00f3w, Poland"},{"name":"Mark Kac Complex Systems Research Centre, Jagiellonian University, \u0141ojasiewicza 11, 30-348 Krak\u00f3w, Poland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9885-253X","authenticated-orcid":false,"given":"Adam","family":"Krawiec","sequence":"additional","affiliation":[{"name":"Institute of Economics, Finance and Management, Jagiellonian University, \u0141ojasiewicza 4, 30-348 Krak\u00f3w, Poland"}]}],"member":"1968","published-online":{"date-parts":[[2020,8,1]]},"reference":[{"key":"ref_1","unstructured":"Landau, L.D., and Lifshitz, E.M. 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