ggplot2の軸とかに数式を使いたい

expression 使えばよろし。

library("mmetrics")
df <- gsummarise(iris, Species, metrics = define(y=sum(Petal.Width)))

ggplot(df, aes(x = Species, y = y)) +
  geom_bar(position = "dodge", color="black", stat="identity") + 
  labs(x = expression(alpha["100"]), y=expression(paste(rho["1"], ", ", rho["2"]))) 

f:id:teramonagi:20190831120015p:plain