Multiplace generalizations of the Seifert form of a classical knot

On the fundamental group $\pi$ of a Seifert surface$A$ of a knot in the three-dimensional sphere, the author constructs, using the same scheme as for the Seifert form, a form $\pi^n\to\mathbf Z$, for $n=3,4,\dots$ . The role of linking coefficient is played here by suitably chosen integral representatives of Milnor residues. It is shown that the form $\pi^3\to\mathbf Z$ can obstruct invertibility, ribbonness and two-sided null-cobordancy of the knot $\partial A$ (even when there is no obstruction by the Seifert form itself).
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Bibliography: 17 titles.