Nullity
The nullity of a link, η(L), is equal to the nullity of A + AT where A is a Seifert Matrix of the link. This is also equal to the rank of the two-fold cover of L.
In general, the nullity of a matrix is equal to the dimension of its null space. In the example of L8n6{0,0} below, we can see from the seifert matrix that the nullity of this link is 1.
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| L8n6{0,0} | Seifert Matrix of L8n6{0,0} (A) | Reduced A+AT L8n6{0,0} |