gistfile1.php

function the_category_filter($thelist,$separator=' ') {
	$childrens = get_categories("child_of=".the_print_category_id());
	$exclude=array();
	$exclude[] = get_category(the_print_category_id())->name;
	$exclude[] = get_category(the_special_category_id())->name;
	foreach($childrens as $category){
		$exclude[] = $category->name;
	}
	$cats = explode($separator,$thelist);
	$newlist = array();
	foreach($cats as $cat) {
		$catname = trim(strip_tags($cat));
		if(!in_array($catname,$exclude))
		$newlist[] = $cat;
	}
	return implode($separator,$newlist);
}
add_filter('the_category','the_category_filter', 10, 2);

...

So it worked!