T:Type, k:, x:T, s:({0..k}T). cons-seq(x;s)  {0..(k+1)}T 

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Definitions	x:A. B(x), , {i..j}, t  T, cons-seq(x;s), if b then t else f fi , P  Q, tt, , P & Q, ff, A, i  j < k, A  B, False, , Unit, P  Q,
Lemmas	bool wf, iff transitivity, assert wf, eqtt to assert, assert of eq int, bnot wf, not wf, eqff to assert, assert of bnot, not functionality wrt iff, le wf, int seg wf