@prefix skos: <http://www.w3.org/2004/02/skos/core#> .

<http://www.irandoc.acir/onto/irandoc/mathpro2791>
  skos:broader <http://www.irandoc.acir/onto/irandoc/mathpro2728> ;
  skos:prefLabel "مسئله کنترل بهینه مختلط"@fa, "problem of mixed optimal control"@en ;
  a <http://www.irandoc.ac.ir/onto/irandoc-meta/Concept>, skos:Concept .

<http://www.irandoc.acir/onto/irandoc/mathpro2728>
  skos:prefLabel "مسائل معادلات دیفرانسیل"@fa, "differential equations problems"@en ;
  a <http://www.irandoc.ac.ir/onto/irandoc-meta/Concept>, skos:Concept ;
  skos:narrower <http://www.irandoc.acir/onto/irandoc/mathpro2791> .