On classical upper bounds for slice genera

P Feller, L Lewark - Selecta Mathematica, 2018 - Springer
We introduce a new link invariant called the algebraic genus, which gives an upper bound
for the topological slice genus of links. In fact, the algebraic genus is an upper bound for …

The four-genus of a link, Levine–Tristram signatures and satellites

M Powell - Journal of Knot Theory and Its Ramifications, 2017 - World Scientific
We give a new proof that the Levine–Tristram signatures of a link give lower bounds for the
minimal sum of the genera of a collection of oriented, locally flat, disjointly embedded …

The topological slice genus of satellite knots

P Feller, AN Miller, J Pinzón-Caicedo - Algebraic & Geometric Topology, 2022 - msp.org
We present evidence supporting the conjecture that, in the topological category, the slice
genus of a satellite knot P (K) is bounded above by the sum of the slice genera of K and P …

Untwisting 3‐strand torus knots

S Baader, I Banfield, L Lewark - Bulletin of the London …, 2020 - Wiley Online Library
We prove that the signature bound for the topological 4‐genus of 3‐strand torus knots is
sharp, using McCoy's twisting method. We also show that the bound is off by at most 1 for 4 …

Balanced algebraic unknotting, linking forms, and surfaces in three-and four-space

P Feller, L Lewark - arXiv preprint arXiv:1905.08305, 2019 - arxiv.org
We provide three 3-dimensional characterizations of the Z-slice genus of a knot, the minimal
genus of a locally-flat surface in 4-space cobounding the knot whose complement has cyclic …

Positive braid knots of maximal topological 4-genus

L Liechti - … Proceedings of the Cambridge Philosophical Society, 2016 - cambridge.org
We show that a positive braid knot has maximal topological 4-genus exactly if it has maximal
signature invariant. As an application, we determine all positive braid knots with maximal …

On calculating the slice genera of 11-and 12-crossing knots

L Lewark, D McCoy - Experimental Mathematics, 2019 - Taylor & Francis
This article contains the results of efforts to determine the values of the smooth and the
topological slice genus of 11-and 12-crossing knots. Upper bounds for these genera were …

On the slice genus of quasipositive knots in indefinite 4-manifolds

D Baraglia - Selecta Mathematica, 2023 - Springer
Let X be a closed indefinite 4-manifold with b+(X)= 3 (mod 4) and with non-vanishing mod 2
Seiberg–Witten invariants. We prove a new lower bound on the genus of a properly …

The four-genus of connected sums of torus knots

C Livingston, CA Van Cott - Mathematical Proceedings of the …, 2018 - cambridge.org
We study the four-genus of linear combinations of torus knots: g4 (aT (p, q)#-bT (p′, q′)).
Fixing positive p, q, p′, and q′, our focus is on the behavior of the four-genus as a function …

Hopf Arborescent Links, Minor Theory, and Decidability of the Genus Defect

P Dehornoy, C Lunel, A de Mesmay - arXiv preprint arXiv:2312.09094, 2023 - arxiv.org
While the problem of computing the genus of a knot is now fairly well understood, no
algorithm is known for its four-dimensional variants, both in the smooth and in the …