Olympic medalists Dennis Hall (Plover, Wis./Sunkist Kids), Garrett Lowney (Freedom, Wis./Minnesota Storm) and Rulon Gardner (Cascade, Colo./Sunkist Kids) all won their respective pools in the first day of competition at the Pytlasinski Tournament in Warsaw, Poland on Friday.    2004 U.S. Nationals champion Justin Ruiz (Colorado Springs, Colo./New York AC) won his first pool match and will compete later against Ezenskas Mindaugas of Poland for the pool championship.    Hall, a 1996 Olympic silver medalist, moved up one weight class to 60 kg/132 lbs. for this tournament, and defeated Tomasz Swierk of Poland 2-1 and Dmitri Shaipak of Belarus 3-0. Hall now advances to the semifinals where he will face Jurij Kohl of Germany.    Lowney, a 2000 Olympic bronze medalist, won his two pool matches at 96 kg/211.5 lbs. to advance. In his pool, Lowney defeated Sergiy Chyzhov of Ukraine 6-0 and Tymur Bayramov of Ukraine 2-0.    Lowney advances to the semifinals. His next opponent is yet to be determined.    Gardner, a 2000 Olympic gold medalist, defeated Oleksandr Petrenko of Ukraine 4-0 and Lukasz Banak of Poland 10-0 to move into the semifinals against Mirian Giorgadze of Georgia.    Also winning matches for the U.S. were Oscar Wood (Fountain, Colo./U.S. Army) at 66 kg/145.5 lbs. and Brad Vering (Colorado Springs, Colo./New York AC) at 84 kg/185 lbs.    U.S. RESULTS  60 kg/132 lbs. - Jim Gruenwald, Colorado Springs, Colo. (Sunkist Kids)  LOSS Nikol Antonkin (Russia), 3-2  LOSS Irakli Tchotchua (Georgia), 2-0, ot, 9:00    60 kg/132 lbs. - Dennis Hall, Plover, Wis. (Sunkist Kids) - advances out of pool  WIN Tomasz Swierk (Poland), 2-1, ot, 9:00  WIN Dmitri Shaipak (Belarus), 3-0    66 kg/145.5 lbs. - Oscar Wood, Fountain, Colo. (U.S. Army)  LOSS Jannis Zamanduridis (Germany), 4-0  WIN Habib Yusifzadze (Azerbaijan), 5-0    74 kg/163 lbs. - Keith Sieracki, Colorado Springs, Colo. (U.S. Army)  LOSS Radoslaw Truszkowski (Poland), 3-0    84 kg/185 lbs. - Brad Vering, Colorado Springs, Colo. (New York AC)  LOSS Viachaslev Makaranka (Belarus), 3-1  WIN Batky Attila (Slovakia), pin  WIN Jim Pettersson (Sweden), 3-0    96 kg/211.5 lbs. - Garrett Lowney, Freedom, Wis. (Minnesota Storm) - advances out of pool  WIN Sergiy Chyzhov (Ukraine), 6-0  WIN Tymur Bayramov (Ukraine), 2-0, ot, 9:00    96 kg/211.5 lbs. - Justin Ruiz, Colorado Springs, Colo. (New York AC)  WIN Roman Meduna (Slovakia), 3-0    120 kg/264.5 lbs. - Rulon Gardner, Cascade, Colo. (Sunkist Kids) - advances out of pool  WIN Oleksandr Petrenko (Ukraine), 4-0  WIN Lukasz Banak (Poland), 10-0