Determining key concepts in documents based on a universal concept graph

A system comprising

• one or more hardware processors;
• and
• a non-transitory machine-readable medium for storing instructions that, when executed by one or more hardware processors, cause the system to perform operations comprising:
• accessing a universal concept graph that includes a first set of nodes that represent concept phrases derived from one or more internal documents associated with a social networking service (SNS) and one or more external documents that are external to the SNS, and a first set of edges that connect a plurality of nodes of the first set of nodes;
• accessing a content object associated with the SNS;
• generating an induced concept graph associated with the content object based on analysis of the content object and the universal concept graph, the induced graph including a second set of nodes that represent one or more concept phrases derived from the content object and a second set of edges that connect a plurality of nodes of the second set of nodes;
• identifying one or more key concept phrases in the content object based on applying one or more key concept selection algorithms to the induced concept graph, a first key concept selection algorithm of the one or more key concept selection algorithms iteratively removing leaf nodes from the induced concept graph associated with the content object until a desired number of nodes representing key concept phrases are left, a leaf node being connected solely to one other node;
• and
• storing the one or more key concept phrases in a record of a database, the record referencing the content object.

A non-transitory machine-readable storage medium comprising instructions that, when executed by one or more hardware processors of a machine, cause the machine to perform operations comprising:

• accessing a universal concept graph that includes a first set of nodes that represent concept phrases derived from one or more internal documents associated with a social networking service (SNS) and one or more external documents that are external to the SNS, and a first set of edges that connect a plurality of nodes of the first set of nodes;
• accessing a content object associated with the SNS;
• generating an induced concept graph associated with the content object based on analysis of the content object and the universal concept graph, the induced graph including a second set of nodes that represent one or more concept phrases derived from the content object and a second set of edges that connect a plurality of nodes of the second set of nodes;
• identifying one or more key concept phrases in the content object based on applying one or more key concept selection algorithms to the induced concept graph, a first key concept selection algorithm of the one or more key concept selection algorithms iteratively removing leaf nodes from the induced concept graph associated with the content object until a desired number of nodes representing key concept phrases are left, a leaf node being connected solely to one other node;
• and
• storing the one or more key concept phrases in a record of a database, the record referencing the content object.