Neuere Entwicklungen in der Theorie der quadratischen Formen. Vortrag, gehalten auf der DMV-Tagung in Stuttgart 1971.
Every real number , has an essentially unique expansion as a Pierce series :where the form a strictly increasing sequence of positive integers. The expansion terminates if and only if is rational. Similarly, every positive real number has a unique expansion as an Engel series :where the form a (not necessarily strictly) increasing sequence of positive integers. If the expansion is infinite, we require that the sequence yi be not eventually constant. Again, such an expansion terminates...
The aim of this article is to present five new examples of modular rigid Calabi-Yau threefolds by giving explicit correspondences to newforms of weight 4 and levels 10, 17, 21 and 73.