<pre><code>let L = \x. T (x x) in
let X = L L in
-X ≡ L L ≡ (\x. T (x x)) L ~~> T (L L) ≡ T X</code></pre>
+X ≡ L L ≡ (\x. T (x x)) L ~~> T (L L) ≡ T X
+</code></pre>
Please slow down and make sure that you understand what justified each
of the equalities in the last line.