2079
Above that , sagging of the overhanging surface is noticed , as well as possible curl , leading to recoater collisions .
 concept or principle: surface; material: as; material: as
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
 Entities: surface, as, as 
Answer:
 concept or principle: surface; material: as; material: as