用ggpairs更改轴标签

Question

我使用ggpairs创建了散点图，我想更改轴标签以包含一些特殊字符，例如希腊字母。谁能告诉我怎么做？

这是我的代码：

library(GGally)
data <- data.frame(
        "Alm"=seq(1,15,0.1), 
        "Blm"=rnorm(141,2.3,0.1),
        "siglm"=rlnorm(141,0.66,0.01),
        "sample"=c(rep("n",50),rep("p",91)
        )
ggpairs(n,columns=c("Alm","Blm","siglm"),colour="sample",diag=list(continuous='density'),axisLabels="none",upper=list(combo="facetdensity",continuous="density",params=c(alpha=0.55)),lower=list(continuous="points"))

我希望轴标签看起来像

labels=c(expression(paste(A[LM])),expression(paste(B[LM])),expression(paste(delta[L])))

感谢您的帮助！