Assuming that the operator documentation is referring to this paper for lenient composition, it gives [X .o. Y] .P. Y as an equivalent expression while Karttunen (1998) gives [X .o. Y] .P. X. The definition in FOMA itself suggests [X .o. Y] .P. X; if so, the documentation should be corrected.
Assuming that the operator documentation is referring to this paper for lenient composition, it gives
[X .o. Y] .P. Yas an equivalent expression while Karttunen (1998) gives[X .o. Y] .P. X. The definition in FOMA itself suggests[X .o. Y] .P. X; if so, the documentation should be corrected.