<｜begin▁of▁sentence｜>### Instruction:
As a Media Buyer, you have been tasked with analyzing the collaborations within the Condensed Matter research field in the year 2005. You have obtained a GML file named cond-mat-2005.gml that contains the network data. Your goal is to apply community detection to identify 3 distinct communities within the network using the principled_clustering function from the cdlib API. Additionally, you need to represent the resulting community structure in JSON format for further analysis and reporting.
### Response:
import networkx as nx
from cdlib import algorithms

# Create a graph from a gml file
G = nx.read_gml('cond-mat-2005.gml')

# Apply the principled clustering algorithm to detect communities
communities = algorithms.principled_clustering(G, cluster_count=3)

# Generate a JSON representation of the detected communities
communities_json = communities.to_json()
print(communities_json)
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