k:, i, j:k. (i, j) = (j, i)  kk 

latex

Definitions	i  j < k, AB, False, (i, j), , if b t else f fi, Unit, P  Q, P & Q, P  Q, i=j, {i..j}, , b, Prop, A, t  T, b, x:A. B(x)
Lemmas	assert wf, not wf, bnot wf, eq int wf, assert of eq int, not functionality wrt iff, assert of bnot, iff transitivity, eqff to assert, eqtt to assert, ifthenelse wf, bool wf, flip wf, nat wf, int seg wf