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In our framework , the structures of classes are conceptualized as a semi-Riemannian manifold which is considered as a submanifold embedded in an ambient semi-Riemannian space .
 used for: semi-Riemannian manifold, structures of classes; part of: submanifold, ambient semi-Riemannian space
Given options, please tell me the relationships of all the listed entity pairs.Output format is "relation1: word1, word2; relation2: word3, word4". 
Option: conjunction, feature of, hyponym of, used for, part of, compare, evaluate for 
Text: {0} 
 Entity Pairs:  semi-Riemannian manifold, structures of classes; submanifold, ambient semi-Riemannian space 
Answer:
 used for: semi-Riemannian manifold, structures of classes; part of: submanifold, ambient semi-Riemannian space