I have two physical chemistry textbooks, one by Atkins and one by Levine, which seem to differ in their notation used when describing Raoult's law.
Atkins talks about the molar fraction term in Raoult's law as if it were of the entire system.
Levine says that Raoult's law has the form $P_i = x^l_i P_i^\circ$, which seems to imply that $x^l_i$ is the molar fraction in the liquid.
So what is it really? And why would Levine use that notation?
Levine also uses this notation for Henry's law.