B. J. Wuebben

collaborators

5 papers

math.GM2026

An exotic $S^{2} \times S^{2}$ and an exotic $CP^{2} # CP^{2}$

Bernd Johannes Wuebben

We prove that a specified Lidman-Piccirillo piece $V$ , a symplectic $4$ -manifold with the homology of $S^{2} \times D^{2}$ built from a genus- $2$ surface bundle over a once-punctured to…

math.GT2026

The instanton homology of the $(- 2, 3, q)$ pretzel knots and Maurer-Cartan deformations in the two-arc algebra of the pillowcase

Bernd Johannes Wuebben

For every odd $q \geq 3$ we prove that the reduced singular instanton knot homology of the pretzel knot $P (- 2, 3, q)$ is free abelian of rank $q + 2$ , by squeezing it between Hironaka's A…

math.GT2026

Traceless $SU (2)$ characters and $Z /4$ instanton gradings for two-bridge and $(3, n)$ -torus knots

Bernd Johannes Wuebben

For the $(3, n)$ -torus knots we determine the $Z /4$ gradings of the reduced singular instanton chain complex through the double branched cover $Σ (2, 3, n)$ rather than throug…

math.DG2026

Slope stability of tangent bundles of smooth toric Fano varieties

Bernd Johannes Wuebben

We classify the anticanonical slope stability of tangent bundles for all $8, 630$ smooth toric Fano varieties in dimensions three through six, by exact evaluation of Klyachko's cr…

q-fin.PM2026

Beyond De Prado and Cotton: Hierarchical and Iterative Methods for General Mean-Variance Portfolios

Bernd Johannes Wuebben

Hierarchical Risk Parity (De Pardo) and the Schur-complement generalization of Cotton are among the most widely adopted regularised portfolio construction methods, yet both are sig…

An exotic S2×S2 and an exotic CP2#CP2

The instanton homology of the (−2,3,q) pretzel knots and Maurer-Cartan deformations in the two-arc algebra of the pillowcase

Traceless SU(2) characters and Z/4 instanton gradings for two-bridge and (3,n)-torus knots

Slope stability of tangent bundles of smooth toric Fano varieties

Beyond De Prado and Cotton: Hierarchical and Iterative Methods for General Mean-Variance Portfolios

An exotic $S^{2} \times S^{2}$ and an exotic $CP^{2} # CP^{2}$

The instanton homology of the $(- 2, 3, q)$ pretzel knots and Maurer-Cartan deformations in the two-arc algebra of the pillowcase

Traceless $SU (2)$ characters and $Z /4$ instanton gradings for two-bridge and $(3, n)$ -torus knots