equation icon  ( ) ( ) Tab = 1-(1 - 2q) gaa' \~/ a'\ ~/ b + gbb' \~/ a\ ~/ b' + 2q - 1- gabgcd' \~/ c \~/ d' 2 2 ( ' ' ) ( ') ( 1 ) 1 - q \~/ a\ ~/ b + gaagbb \~/ a'\ ~/ b' + qgab \~/ c\ ~/ c + \~/ c' \~/ c + q Rab --gabR - -m2gab, (50) 2 2