# extenders contain more introduction than redefinitions
	private fun is_extender(filter: ModelFilter): Bool do
		var rdfs = collect_redef_mproperties(filter).length
		var news = collect_intro_mproperties(filter).length
		var locs = collect_local_mproperties(filter).length
		if news > rdfs and locs > 0 then return true
		return false
	end