Nuprl Lemma : rank-pi-choices
∀[P:pi_term()]. ∀[choice:{c:pi_prefix() × pi_term()| (c ∈ pi-choices(P))} ].  pi-rank(snd(choice)) < pi-rank(P)
Proof
Definitions occuring in Statement : 
pi-choices: pi-choices(t), 
pi-rank: pi-rank(p), 
pi_term: pi_term(), 
pi_prefix: pi_prefix(), 
l_member: (x ∈ l), 
less_than: a < b, 
uall: ∀[x:A]. B[x], 
pi2: snd(t), 
set: {x:A| B[x]} , 
product: x:A × B[x]
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
so_lambda: λ2x.t[x], 
prop: ℙ, 
so_apply: x[s], 
subtype_rel: A ⊆r B, 
implies: P ⇒ Q, 
pi-rank: pi-rank(p), 
pi-choices: pi-choices(t), 
pizero: pizero(), 
pi_term_ind: pi_term_ind(v;zero;pre,body,rec1....;left,right,rec2,rec3....;left,right,rec4,rec5....;body,rec6....;name,body,rec7....), 
all: ∀x:A. B[x], 
uimplies: b supposing a, 
not: ¬A, 
false: False, 
picomm: picomm(pre;body), 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
pioption: pioption(left;right), 
pipar: pipar(left;right), 
pirep: pirep(body), 
pinew: pinew(name;body), 
guard: {T}, 
nat: ℕ, 
pi2: snd(t), 
decidable: Dec(P), 
or: P ∨ Q, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
exists: ∃x:A. B[x], 
top: Top, 
ge: i ≥ j 
Latex:
\mforall{}[P:pi\_term()].  \mforall{}[choice:\{c:pi\_prefix()  \mtimes{}  pi\_term()|  (c  \mmember{}  pi-choices(P))\}  ].
    pi-rank(snd(choice))  <  pi-rank(P)
Date html generated:
2016_05_17-AM-11_25_53
Last ObjectModification:
2016_01_18-AM-07_48_24
Theory : event-logic-applications
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