Existence of infinitely many homotopy classes from ${\mathbb{S}}^3$ to ${\mathbb{S}}^2$ having a minimimzing $W^{s,\frac{3}{s}}$-harmonic map

Adam Grzela, Katarzyna Mazowiecka

In 1998 T. Rivière proved that there exist infinitely many homotopy classes of ${\pi }_3({\mathbb{S}}^2)$ having a minimizing 3-harmonic map. This result is especially surprising taking in…