D:\sbornik\...\TPEL.DVI Mathematical Problems of Computer Science 32, 23{26, 2009. T he M inimum Linear Ar r angement P r oblem on B ipar tite ¡-or iented Gr aphs L e vo n R . R a fa ye lya n Yerevan State University levonr@synopsys.com Abstract In general case the minimum linear arrangement (MINLA) problem is NP-complete. It is NP-complete also for bipartite graphs. In this paper it is proved that a minimum linear arrangement for bipartite ¡-oriented graphs can be found in polynomial time. The formula for the cost of optimal arrangement is given as well. Refer ences [1 ] M. R . Ga r e y, D . S . Jo h n s o n ,Computers and Intractability. A g u id e t o t h e t h e o r y o f N P -c o m p le t e n e s s . Fr e e m a n a n d Co m p a n y, 1 9 7 9 . [2 ] S . E ve n , Y . S h ilo a h , N P -c o m p le t e n e s s o f s e ve r a l a r r a n g e m e n t p r o b le m s , R e p o r t N o . 4 3 , D e p t . o f Co m p u t e r S c ie n c e , Te c h n io n , H a ifa , Is r a e l, 1 9 7 5 . ØÇÝÇÙ³É ·Í³ÛÇÝ Ñ³Ù³ñ³Ï³ÉáõÙ ËݹñÇ ÉáõÍáõÙÁ »ñÏÏáÕÙ³ÝÇ ¡ -ÏáÕÙÝáñáßí³Í ·ñ³ýÝ»ñÇ Ñ³Ù³ñ È. è³ý³Û»ÉÛ³Ý ²Ù÷á÷áõÙ ¶ñ³ýÇ ÙÇÝÇÙ³É ·Í³ÛÇÝ Ñ³Ù³ñ³Ï³ÉáõÙ ËݹÇñÁ ÁݹѳÝáõñ ¹»åùáõÙ NP- ÉñÇí ¿: ²ÛÝ NP- ÉñÇí ¿ ݳ¨ »ñÏÏáÕÙ³ÝÇ ·ñ³ýÝ»ñÇ Ñ³Ù³ñ: ²Ûëï»Õ ³å³óáõóí³Í ¿, áñ »ñÏÏáÕÙ³ÝÇ ¡ -ÏáÕÙÝáñáßí³Í ·ñ³ýÝ»ñÇ Ñ³Ù³ñ ÙÇÝÇÙ³É ·Í³ÛÇÝ Ñ³Ù³ñ³Ï³Éáõ٠ϳñ»ÉÇ ¿ ·ïÝ»É µ³½Ù³Ý¹³Ù³ÛÇÝ Å³Ù³Ý³ÏáõÙ: îñí³Í ¿ ݳ¨ ûåïÇÙ³É ÉáõÍÙ³Ý ³ñÅ»ùÝ»ñÇ Ñ³ßí³ñÏáÕ µ³Ý³Ó¨Á: 2 3