:: deftheorem defines Baire WAYBEL12:def 6 :
for T being non empty TopSpace holds
( T is Baire iff for F being Subset-Family of T st F is countable & ( for S being Subset of T st S in F holds
( S is open & S is dense ) ) holds
ex I being Subset of T st
( I = Intersect F & I is dense ) );