title: How to create lattice plot title with new line, italics and variable names in R
body: <p>I've been trying to add a title (via main) to a map created with spplot that consists of two lines of text, but with the second line italicised. The text in each line is drawn from a variable name. I've variously tried using bquote and expression, but with no luck. </p>
  
  <p>A basic example of my starting point is below, although in my actaul usage the text for a and b are drawn iteratively from a vector as part of a loop. Any suggestions as to how to keep the two lines split as per the example, but with the second line of text italicised would be much appreciated. I hope the example is clear. Thanks in advance.</p>
  
  <pre><code>require(sp)
  data(meuse)
  coordinates(meuse)&lt;-~x+y
  
  a&lt;-"line 1"
  b&lt;-"line 2"
  title&lt;-paste(a,'\n',b,sep="")
  
  spplot(meuse,c("ffreq"),col.regions="black",main=title)
  </code></pre>