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<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Publishing DTD v1.0 20120330//EN" "JATS-journalpublishing1.dtd"><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" article-type="research-article"><front><journal-meta><journal-id journal-id-type="publisher-id">INFORMATICA</journal-id><journal-title-group><journal-title>Informatica</journal-title></journal-title-group><issn pub-type="epub">0868-4952</issn><issn pub-type="ppub">0868-4952</issn><publisher><publisher-name>VU</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="publisher-id">INF10406</article-id><article-id pub-id-type="doi">10.3233/INF-1999-10406</article-id><article-categories><subj-group subj-group-type="heading"><subject>Research article</subject></subj-group></article-categories><title-group><article-title>On the Population Evolution Problem with the Harmonic Mean Type Mating Law and Females' Pregnancy</article-title></title-group><contrib-group><contrib contrib-type="Author"><name><surname>Skakauskas</surname><given-names>Vladas</given-names></name><email xlink:href="mailto:vladas.skakauskas@maf.vu.lt">vladas.skakauskas@maf.vu.lt</email><xref ref-type="aff" rid="j_INFORMATICA_aff_000"/></contrib><aff id="j_INFORMATICA_aff_000">Faculty of Mathematics and Informatics, Vilnius University, Naugarduko 24, 2600 Vilnius, Lithuania</aff></contrib-group><pub-date pub-type="epub"><day>01</day><month>01</month><year>1999</year></pub-date><volume>10</volume><issue>4</issue><fpage>441</fpage><lpage>456</lpage><history><date date-type="received"><day>01</day><month>05</month><year>1999</year></date></history><abstract><p>A model for an age-sex-structured nonlimited population dynamics with the harmonic mean type mating law and females' pregnancy is presented. The existence and uniqueness theorem for the general case of vital rates is proved, the extinction and growth of the population are considered, and a class of the product (separable) solutions is obtained.</p></abstract><kwd-group><label>Keywords</label><kwd>population dynamics</kwd><kwd>random mating</kwd><kwd>age-sex-structured population</kwd></kwd-group></article-meta></front></article>