A structured analysis of Hubble tension
  As observations of the Hubble parameter from both early and late sources have
improved, the tension between these has increased to be well above the
5$\sigma$ threshold. Given this, the need for an explanation of such a tension
has grown. In this paper, we explore a set of 7 assumptions, and show that, in
order to alleviate the Hubble tension, a model needs to break at least one of
these 7, providing a quick and easy to apply check for new model proposals. We
also use this framework to make a rough categorisation of current proposed
models, and show the existence of at least one under-explored avenue of
alleviating the Hubble tension.
