What is meant by Empty Hyperedge?

hi,

this the hypergraph file being created for my matrix of nhedges=7 ,nvxts=7.

7 7
4 5 6
0 1
0 2
0 3
1 4
2 5
3 6

i have given this file as input to the hmetis executable file with parameters 2 5 10 1 1 3 0 24
the ouput read some thing like this which i did not understand.

Empty Hyperedge #2

can some one please help me fast?

sravan