The abundance of the objects with splitted nuclei among the candidates - the members of tight systems can be explained by the existence of bright HII regions in their central parts and also by the existence of dust lanes in their nuclear regions. 270 objects out of our lists are listed in IRAS catalogue.
We propose results about sign-constancy of Green's functions to impulsive nonlocal boundary value problems in a form of theorems about differential inequalities. One of the ideas of our approach is to construct Green's functions of boundary value problems for simple auxiliary differential equations with impulses. Careful analysis of these Green's functions allows us to get conclusions about the sign-constancy of Green's functions to given functional differential boundary value problems, using the technique of theorems about differential and integral inequalities and estimates of spectral radii of the corresponding compact operators in the space of essential bounded functions.