Having latex-like math formula in the legend

Question

I know how to generate this in the legend:

N_{1}(\alpha)

which can be done via

expression(N[1](alpha))

But I need something like this in latex:

N_{1+}(\LargerCdot \alpha)

which I have no clue how to generate.

Answer 1

Here are a few options:

1) Regular dot

expression(N[1+NULL](NULL %.% alpha))

2) Large dot: On the Mac, I used option + 8 to get the large dot.

expression(paste(N[1+NULL],"(•", alpha,")"))
expression(paste(N[1+NULL],"(",~"•",NULL~alpha,")"))

Example using built-in iris data frame and ggplot2:

library(ggplot2)

ggplot(iris, aes(Sepal.Width, Sepal.Length)) +
  geom_point(aes(colour=Species)) +
  scale_colour_discrete(labels=c(expression(N[1+NULL](NULL %.% alpha)), 
                                 expression(paste(N[1+NULL],"(•", alpha,")")),
                                 expression(paste(N[1+NULL],"(",~"•",NULL~alpha,")")))) +
  theme(legend.text=element_text(size=15))