epidemics on graphs

[slwu89]

2 possibilities:

• HasGraph type hierarchy https://github.com/AlgebraicJulia/Catlab.jl/blob/master/src/graphs/BasicGraphs.jl#L45
• data migration https://www.algebraicjulia.org/assets/slides/topos-colloquium-2021.pdf

Perhaps data migration is to be preferred for static contact networks and dynamic networks should use the type hierarchy?