Okay, this is backwards from the usual. Sagemath failed for some odd reason and a reinstall didn't work. In the meantime, though, I've installed Anaconda, which has the Juptyer notebook, which accepts the Sagemath kernel. Is it possible to install the kernel into Jupyter, rather than the usual, in which sagemath installs jupyter? A kernel is a kernel so it seems possible but I've looked around and can't find a way. It only seems to work in Linux and I'm using Windows.