problem([]==>t:int tree=>geq(maxht(t),minht(t)),
ind_strat(induction(lemma(treeind)-[(t:int tree)-node(v1,v0)])then[base_case(sym_eval(normalize_term([reduction([1],[maxht1,equ(pnat,left)]),reduction([],[geqzero,equiv(left)]),reduction([1,1],[minht1,equ(pnat,left)])]))then[elementary(identity)]),step_case(ripple(direction_out,wave(direction_out,[2],[minht2,equ(pnat,left)],[])then[wave(direction_out,[1],[maxht2,equ(pnat,left)],[])then[wave(direction_out,[],[geq3,equ(u(1),left)],[])then[unblock_then_wave(direction_out,unblock_lazy([unblock(meta_ripple,unused,unused),unblock(meta_ripple,unused,unused),idtac])then wave(direction_out,[],[minmaxgeq,imp(right)],[]))]]])then[idtac])]),lambda(t,su(lambda(v4,su(su(su(su(su(v8,[v7 of t],[v8]),[v6 of lambda(v1,lambda(v0,lambda(v2,lambda(v3,su(su(su(su(su(su(su(su(su(su(su(su(su(su(su(v4,[v7 of _213083],[v4]),[v6 of minht(v0)],[v7]),[v5 of minht(v1)],[v6]),[v4 of maxht(v0)],[v5]),[minmaxgeq of maxht(v1)],[v4]),[term_of(minmaxgeq)],[minmaxgeq]),[v4 of min(minht(v1),minht(v0))],[v5]),[geq3 of max(maxht(v1),maxht(v0))],[v4]),[term_of(geq3)],[geq3]),[v4 of v0],[v5]),[maxht2 of v1],[v4]),[term_of(maxht2)],[maxht2]),[v4 of v0],[v5]),[minht2 of v1],[v4]),[term_of(minht2)],[minht2])))))],[v7]),[v5 of lambda(v0,su(su(su(su(spread(v1,[v2,v3,su(v5,[v3 of su(su(axiom,[minht1 of v0],[v1]),[term_of(minht1)],[minht1])],[v5])]),[geqzero of minht(leaf(v0))],[v1]),[term_of(geqzero)],[geqzero]),[maxht1 of v0],[v1]),[term_of(maxht1)],[maxht1]))],[v6]),[v3 of lambda(t,geq(maxht(t),minht(t)))],[v5]),[v4 of int],[v3]))of v2,[term_of(treeind)],[v2])),
[problem([t:int tree,v1:int tree,v0:int tree,v2:geq(maxht(v1),minht(v1)),v3:geq(maxht(v0),minht(v0))]==>geq(maxht(v1),minht(v1))#geq(maxht(v0),minht(v0)),
 elementary(intro then[hyp(v2),hyp(v3)]),v2&v3,
 [
 ]) ext _213083
]).
