Nuprl Lemma : strat2play-reachable
∀g:SimpleGame. ∀n:ℕ. ∀s:win2strat(g;n). ∀moves:strat2play(g;n;s).
  ((||moves|| ≤ ((2 * n) + 2)) 
⇒ (moves ∈ sequence({p:Pos(g)| sg-reachable(g;InitialPos(g);p)} )))
Proof
Definitions occuring in Statement : 
sg-reachable: sg-reachable(g;x;y)
, 
strat2play: strat2play(g;n;s)
, 
win2strat: win2strat(g;n)
, 
play-len: ||moves||
, 
sg-init: InitialPos(g)
, 
sg-pos: Pos(g)
, 
simple-game: SimpleGame
, 
sequence: sequence(T)
, 
nat: ℕ
, 
le: A ≤ B
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
set: {x:A| B[x]} 
, 
multiply: n * m
, 
add: n + m
, 
natural_number: $n
Definitions unfolded in proof : 
guard: {T}
, 
uiff: uiff(P;Q)
, 
uimplies: b supposing a
, 
le: A ≤ B
, 
and: P ∧ Q
, 
lelt: i ≤ j < k
, 
int_seg: {i..j-}
, 
pi2: snd(t)
, 
pi1: fst(t)
, 
seq-len: ||s||
, 
seq-item: s[i]
, 
play-len: ||moves||
, 
play-item: moves[i]
, 
sequence: sequence(T)
, 
so_apply: x[s]
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
nat: ℕ
, 
squash: ↓T
, 
subtype_rel: A ⊆r B
, 
uall: ∀[x:A]. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
all: ∀x:A. B[x]
Lemmas referenced : 
squash_wf, 
all_wf, 
sg-init_wf, 
sg-reachable_wf, 
lelt_wf, 
less_than_transitivity1, 
multiply-is-int-iff, 
int_subtype_base, 
set_subtype_base, 
add-is-int-iff, 
simple-game_wf, 
win2strat_wf, 
strat2play_wf, 
play-len_wf, 
equal_wf, 
nat_wf, 
seq-len_wf, 
le_wf, 
sg-pos_wf, 
sequence_wf, 
set_wf, 
int_seg_wf, 
strat2play_subtype, 
play-item-reachable
Rules used in proof : 
setEquality, 
functionEquality, 
independent_isectElimination, 
intEquality, 
closedConclusion, 
baseApply, 
independent_pairFormation, 
dependent_set_memberEquality, 
functionExtensionality, 
dependent_pairEquality, 
productElimination, 
independent_functionElimination, 
lambdaEquality, 
equalitySymmetry, 
equalityTransitivity, 
because_Cache, 
multiplyEquality, 
addEquality, 
natural_numberEquality, 
imageElimination, 
baseClosed, 
imageMemberEquality, 
rename, 
setElimination, 
applyLambdaEquality, 
sqequalRule, 
applyEquality, 
isectElimination, 
hypothesisEquality, 
thin, 
dependent_functionElimination, 
sqequalHypSubstitution, 
hypothesis, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
extract_by_obid, 
introduction, 
cut
Latex:
\mforall{}g:SimpleGame.  \mforall{}n:\mBbbN{}.  \mforall{}s:win2strat(g;n).  \mforall{}moves:strat2play(g;n;s).
    ((||moves||  \mleq{}  ((2  *  n)  +  2))  {}\mRightarrow{}  (moves  \mmember{}  sequence(\{p:Pos(g)|  sg-reachable(g;InitialPos(g);p)\}  )))
Date html generated:
2018_07_25-PM-01_33_58
Last ObjectModification:
2018_06_20-AM-10_53_45
Theory : co-recursion
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