Premise: The 1982 Federation Cup was the 20th edition of the most important competition between national teams in women 's tennis . The Grand Slam tournaments , also called majors , are the four most-important annual tennis events . Margaret Court ( née Smith ; born 16 July 1942 ) , also known as Margaret Smith Court , is a retired Australian tennis player and former world No. 1 . Martina Navratilova . Navratilova is one of just three women ever to have accomplished a Career Grand Slam in singles , women 's doubles , and mixed doubles ( called the Grand Slam `` boxed set '' ) , a distinction she shares with Margaret Court and Doris Hart . The WTA Finals ( formerly known as the WTA Tour Championships short : WTA Championships ) , is a professional tennis tournament played annually at the end of the season for the top-ranked players on the Women 's Tennis Association ( WTA ) tour .
Hypothesis: Martina Navratilova is an athlete.
Label: ENTAILMENT