Three U.S. wrestlers are unbeaten after the first day of competition at the Women's World Wrestling Championships, to be held in Sofia, Bulgaria, September 1.     The athletes were competing in their pool competition on Friday. All six U.S. wrestlers will continue to wrestle on Saturday .    Winning her first two matches and capturing her three-person pool was Kristie Marano (Albany, N.Y./ATWA) at 149.75 pounds. With the victories, Marano has clinched a spot in the semifinals, where she will face Galina Ivanova of Bulgaria.    Marano pinned her first two opponents, stopping Sakizligi Gamze of Turkey in 5:16 and planting Ewelina Pruszko of Poland in 2:26. Marano has finished second in the past four World Championships, competing at 165.25 pounds. She dropped to 149.75 pounds for the first time this year.      U.S. wrestlers with victories in their first match were Patricia Miranda (Saratoga, Calif./Dave Schultz WC) at 123.25 pounds and Sara McMann (Lock Haven, Pa./Sunkist Kids) at 136.5 pounds. Both are competing in their first World Championships.    Miranda scored an impressive 12-2 technical fall over Wu Li-Chauan of Taipei. Her next pool opponent on Saturday is Semra Aydin of Turkey.    McMann pinned  Sofia Kampanari of Greece in 37 seconds in the first match. She will face four-time World Champion Nikola Hartmann of Austria in her second pool match on Saturday.    If Miranda and McMann win their second matches, they will move into the championships bracket and remain eligible for a medal.    The three U.S. wrestlers who lost their first match were Clarrisa Chun (Kapolei, Hawaii/Viking WC) at 101.25 pounds, Tina George Wilson (Colorado Springs, Colo./Sunkist Kids) at 123.25 pounds and Iris Smith (Colorado Springs, Colo./Sunkist Kids) at 165.25 pounds.    Chun lost by pin to Maria de los Angelos Barraza of Mexico in 4:20. Her next opponent in the pool is Inga Karamchakova of Russia, a two-time World bronze medalist.    George-Wilson dropped a 9-5 decision to Constantina Tsimpanakou of Greece in her first match. Her next opponent on Saturday is Tatiana Lazareva of Ukraine. George was sixth in the 1999 World Championships     Smith opened with a loss by pin to 1998 World bronze medalist Edyta Witkowska of Poland in 4:20. Her next opponent is Yildirim Zarife of Turkey.    The competition will be held in the hall "Universiada" in Sofia.  Competition continues in all six weight classes on Saturday, September 2 and Sunday, September 3. The United States is the defending World Team champions in women's wrestling.    The U.S. team is led by co-head coach Rob Eiter of Chicago, Ill., and USA Wrestling National Women's Coach Mike Duroe of Colorado Springs, Colo. Co-head coach Jack Griffin of Evanston, Ill. could not attend but participated in the training camp.    WOMEN'S WORLD WRESTLING CHAMPIONSHIPS at Sofia, Bulgaria, Sept. 1    U.S. results on Friday    46 kg/101.25 lbs. - Clarrisa Chun, Kapolei, Hawaii (Viking WC) - lost pin to Maria de los Angelos Barraza (Mexico), 4:20    51 kg/112.25 lbs - Patricia Miranda, Saratoga, Calif. (Dave Schultz WC) - won by tech. fall over Wu Li-Chauan (Taipei), 12-1    56 kg/123.25 lbs. - Tina George-Wilson, Colorado Springs, Colo. (Sunkist Kids) - lost dec. to Constantina Tsimpanakou (Greece), 9-5    62 kg/136.5 lbs. - Sara McMann, Lock Haven, Pa. (Sunkist Kids) - pin Sofia Kampanari (Greece), 0:37    69 kg/149.75 lbs. - Kristie Marano, Albany, N.Y. (ATWA) - pin Sakizligi Gamze (Turkey), 5:16; pin Ewelina Pruszko (Poland), 2:26    75 kg/165.25 lbs. - Iris Smith, Colorado Springs, Colo. (Sunkist Kids) - lost pin to Edyta Witkowska (Poland), 4:20    Second day pairings on Saturday    46 kg/101.25 lbs. - Clarrisa Chun, Kapolei, Hawaii (Viking WC) - vs. Inga Karamchakova (Russia)    51 kg/112.25 lbs - Patricia Miranda, Saratoga, Calif. (Dave Schultz WC) - vs. Semra Aydin (Turkey)    56 kg/123.25 lbs. - Tina George-Wilson, Colorado Springs, Colo. (Sunkist Kids) - vs. Tatiana Lazareva (Ukraine)    62 kg/136.5 lbs. - Sara McMann, Lock Haven, Pa. (Sunkist Kids) -  vs. Nikola Hartmann (Austria)    69 kg/149.75 lbs. - Kristie Marano, Albany, N.Y. (ATWA) - qualified for the semifinals against Galina Ivanova (Bulgaria)    75 kg/165.25 lbs. - Iris Smith, Colorado Springs, Colo. (Sunkist Kids) - vs. Yildirim Zarife (Turkey)