1903
Based on the geometrization of class structures , optimizing class structures in the feature space is equivalent to maximizing the quadratic quantities of metric tensors in the semi-Riemannian space .
 feature of: feature space, class structures; feature of: semi-Riemannian space, quadratic quantities of metric tensors
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:  feature space, class structures; semi-Riemannian space, quadratic quantities of metric tensors 
Answer:
 feature of: feature space, class structures; feature of: semi-Riemannian space, quadratic quantities of metric tensors