We give a topological interpretation of the core group invariant of a surface embedded in ${{S}^{4}}\,\left[ \text{F-R} \right],\,\left[ \text{Ro} \right]$. We show that the group is isomorphic to the free product of the fundamental group of the double branch cover of ${{S}^{4}}$ with the surface as a branched set, and the infinite cyclic group. We present a generalization for unoriented surfaces, for other cyclic branched covers, and other codimension two embeddings of manifolds in spheres.

Let ${{X}^{5}}\,+\,aX\,+\,b\,\in \,Z\left[ X \right]$ have Galois group ${{D}_{5}}$. Let $\theta $ be a root of ${{X}^{5}}\,+\,aX\,+\,b$. An explicit formula is given for the discriminant of $Q\left( \theta \right)$.

Applications of minimal surface methods are made to obtain information about univalent harmonic mappings. In the case where the mapping arises as the Poisson integral of a step function, lower bounds for the number of zeros of the dilatation are obtained in terms of the geometry of the image.