YES

1 decompositions
 #1 -----------
   1: or(x1,T()) -> T()
   2: or(x1,F()) -> x1
   3: or(x1,x2) -> or(x2,x1)

@Jouannaud and Kirchner's criterion
--- R
   1: or(x1,T()) -> T()
   2: or(x1,F()) -> x1
   3: or(x1,x2) -> or(x2,x1)

--- S
   1: or(x1,T()) -> T()
   2: or(x1,F()) -> x1
   3: or(x1,x2) -> or(x2,x1)