Relations (of posts terms...) (tag)
| cat_is_ancestor_of() | Checks if the specified category is a child of another specified category (all nesting levels are checked). Conditional tag. |
| get_adjacent_post() | Gets the object of the adjacent (next or previous) post from the specified taxonomy (the default is category). |
| get_ancestors() | Get an array of ancestor IDs for a given object. |
| get_category_parents() | Retrieve category parents with separator. |
| get_next_post() | Retrieves the next post (as object) from the specified taxonomy (the default is category). |
| get_post_ancestors() | Retrieve ancestors of a post. |
| get_previous_post() | Retrieves the previous post (as object) from the specified taxonomy (the default is category). |
| get_term_children() | Merge all term children into a single array of their IDs. |