= Signature of a knot
{title2=$\sigma(K)=\operatorname{sign}(V+V^T)$}
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= Knot signature
{synonym}
The knot signature is the <signature> of the symmetrized <Seifert matrix>. Equivalently it is the <signature> of the double <branched covering> of $B^4$ over a pushed-in <Seifert surface>. At $\omega=-1$ it agrees with the <Levine-Tristram signature>. It is additive under <connected sum of knots>, changes sign under reflection, and obeys $|\sigma(K)|\leq2g_4(K)$. State the ambient <orientation> and push-off convention when assigning a sign.
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