what are the upper material classes of wood?
Entity Entity Entity Entity Entity Entity Entity Entity Entity Entity Entity
m.08g852 m.015_77 m.09wzt m.0cffdh m.03q7mtg m.03q7mvk m.03qrcx2 m.03qrcw4 m.03q7mxx m.04f0r14 m.0n489mx
Tilia americana Walnut Oak Maple tree American walnut redwood Balsa wood Beechwood teak Stave Thermally modified wood
class entity
engineering.material m.083vt
engineering.material engineering.material
Material Wood
none none
engineering.material.parent_material_class
Parent material class
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> PREFIX : <http://rdf.freebase.com/ns/> 
SELECT (?x0 AS ?value) WHERE {
SELECT DISTINCT ?x0  WHERE { 
?x0 :type.object.type :engineering.material . 
VALUES ?x1 { :m.083vt } 
?x0 :engineering.material.parent_material_class ?x1 . 
FILTER ( ?x0 != ?x1  )
}
}
(AND engineering.material (JOIN engineering.material.parent_material_class m.083vt))