I don't see where the Philadelphia Orchestra has announced anything of the
sort.  They DO say the following: "Over the course of its 100 years, The
Philadelphia Orchestra has given either world or United States premieres of
well over 300 works.  For the 100th anniversary season, the Orchestra has
selected fifteen works that represent the best of the music that the
Orchestra has INTRODUCED (emphasis mine)"

They also say "1999-2000 Season Premieres: Since presentation of new music
is a major component of The Philadelphia Orchestra' s heritage the 100th
season will offer numerous works new to Philadelphia Orchestra audiences.
The 1999-2000 season will feature two world premieres, both commissioned
by the Orchestra for its Centennial Celebration, and twelve Philadelphia
Orchestra premieres." For the 1999-2000 season, the Orchestra will premiere
the first two of these commissions: (Hannibal's _One Heart Beating_ and
Rautavaara's _8th Symphony_)."

I do see how some people could get the impression that the Philadelphia
Orchestra is on the cutting edge of performance of 20th century music from
viewing their website.  The fact remains however, that precious little
music from post World War II (almost two-thirds of the 20th century) is on
their roster.

Dick Hihn