Functions leading to \bot are more useful
Make a simpler version of x==a
<-==-trans
Have both versions of condition on parameter n.
Prove a general version of step1 - lambda-unequal
Prove that lambda e1 f is equal to lambda e f when e # e1

This is more general than what was proved before specifically when e
was a point and e1 was a line
Make # and <> parameters irrelevant
Define the bijection of Lemma 2.1