Andrew Willshire wrote an article The Spectator titled How Number 10 should illustrate its Covid alert formula.
« A complex number has a real part (the everyday numbers with which we are familiar) and an imaginary part (which is a multiple of the square root of minus one). »
« On this basis, we can see that we simply need to treat the Covid alert level as a kind of complex number and plot it on a 2D plane. »
« Highlighted in blue is the position the UK is currently in, with our number of confirmed infections and a broad estimate of R being close to 1. As can be seen on the graph, that places us around the transition from red to orange – the level the Prime Minister suggested the country was in on Sunday evening. »
[ Corona virus, COVID-19 ]