Is it obligatory to maintain ties of kinship with the son of the brother, the son of the sister, the son of the maternal uncle, and the son of the paternal uncle? And what are the ties of kinship?

"Kinship" and "womb" (as in "ties of the womb") share a similar meaning. Scholars have differed regarding which relatives the command to maintain ties of kinship applies to. Some have held that it includes everyone with whom a person shares lineage or kinship. Others have confined it to only those relatives with whom marriage is prohibited (due to consanguinity). This latter view is the preferred one according to us. Based on this, the son of a brother and the son of a sister are among those whose ties must be maintained. As for the son of a maternal uncle and the son of a paternal uncle, maintaining ties with them is not obligatory according to the preponderant opinion.