graph G {
"Index (information technology)" -- "Index (search engine)" [penwidth = "4"];
"Index (information technology)" -- "Dissertation"[style=invis];
"Index (information technology)" -- "Machine learning"[style=invis];
"Index (information technology)" -- "Keywords"[style=invis];
"Index (information technology)" -- "Natural language" [penwidth = "3"];
"Index (information technology)" -- "Knowledge"[style=invis];
"Index (information technology)" -- "Information retrieval" [penwidth = "3"];
"Index (information technology)" -- "Algorithm" [penwidth = "3"];
"Index (information technology)" -- "Training set"[style=invis];
"Index (search engine)" -- "Dissertation"[style=invis];
"Index (search engine)" -- "Machine learning" [penwidth = "3"];
"Index (search engine)" -- "Keywords"[style=invis];
"Index (search engine)" -- "Natural language" [penwidth = "3"];
"Index (search engine)" -- "Knowledge"[style=invis];
"Index (search engine)" -- "Information retrieval" [penwidth = "4"];
"Index (search engine)" -- "Algorithm" [penwidth = "3"];
"Index (search engine)" -- "Training set"[style=invis];
"Dissertation" -- "Machine learning" [penwidth = "1"];
"Dissertation" -- "Keywords"[style=invis];
"Dissertation" -- "Natural language" [penwidth = "2"];
"Dissertation" -- "Knowledge" [penwidth = "2"];
"Dissertation" -- "Information retrieval" [penwidth = "1"];
"Dissertation" -- "Algorithm" [penwidth = "2"];
"Dissertation" -- "Training set"[style=invis];
"Machine learning" -- "Keywords"[style=invis];
"Machine learning" -- "Natural language" [penwidth = "3"];
"Machine learning" -- "Knowledge" [penwidth = "2"];
"Machine learning" -- "Information retrieval" [penwidth = "4"];
"Machine learning" -- "Algorithm" [penwidth = "3"];
"Machine learning" -- "Training set" [penwidth = "4"];
"Keywords" -- "Natural language"[style=invis];
"Keywords" -- "Knowledge"[style=invis];
"Keywords" -- "Information retrieval"[style=invis];
"Keywords" -- "Algorithm" [penwidth = "2"];
"Keywords" -- "Training set"[style=invis];
"Natural language" -- "Knowledge" [penwidth = "3"];
"Natural language" -- "Information retrieval" [penwidth = "3"];
"Natural language" -- "Algorithm" [penwidth = "3"];
"Natural language" -- "Training set"[style=invis];
"Knowledge" -- "Information retrieval" [penwidth = "2"];
"Knowledge" -- "Algorithm" [penwidth = "2"];
"Knowledge" -- "Training set"[style=invis];
"Information retrieval" -- "Algorithm" [penwidth = "3"];
"Information retrieval" -- "Training set" [penwidth = "3"];
"Algorithm" -- "Training set" [penwidth = "2"];
}