Nuprl Lemma : strat2play-invariant-1

∀g:SimpleGame. ∀n:ℕ. ∀s:win2strat(g;n). ∀moves:strat2play(g;n;s).
  ((moves[0] = InitialPos(g) ∈ Pos(g))
  ∧ (∀i:ℕn + 1
       ((↓Legal1(moves[2 * i];moves[(2 * i) + 1]))
       ∧ (i < n
         ⇒ ((↓Legal2(moves[(2 * i) + 1];moves[2 * (i + 1)]))
            ∧ (moves[2 * (i + 1)] = (s play-truncate(moves;2 * (i + 1))) ∈ Pos(g)))))))


Proof




Definitions occuring in Statement :  strat2play: strat2play(g;n;s),  win2strat: win2strat(g;n),  play-truncate: play-truncate(f;m),  play-item: moves[i],  sg-legal2: Legal2(x;y),  sg-legal1: Legal1(x;y),  sg-init: InitialPos(g),  sg-pos: Pos(g),  simple-game: SimpleGame,  seq-item: s[i],  int_seg: {i..j-},  nat: ℕ,  less_than: a < b,  all: ∀x:A. B[x],  squash: ↓T,  implies: P ⇒ Q,  and: P ∧ Q,  apply: f a,  multiply: n * m,  add: n + m,  natural_number: $n,  equal: s = t ∈ T
Definitions unfolded in proof :  all: ∀x:A. B[x],  uall: ∀[x:A]. B[x],  member: t ∈ T,  nat: ℕ,  implies: P ⇒ Q,  false: False,  ge: i ≥ j ,  guard: {T},  uimplies: b supposing a,  prop: ℙ,  and: P ∧ Q,  squash: ↓T,  int_seg: {i..j-},  le: A ≤ B,  less_than': less_than'(a;b),  not: ¬A,  decidable: Dec(P),  or: P ∨ Q,  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  uiff: uiff(P;Q),  subtract: n - m,  subtype_rel: A ⊆r B,  top: Top,  true: True,  strat2play: strat2play(g;n;s),  eq_int: (i =z j),  ifthenelse: if b then t else f fi ,  btrue: tt,  cand: A c∧ B,  sq_type: SQType(T),  lelt: i ≤ j < k,  win2strat: win2strat(g;n),  bfalse: ff,  so_lambda: λ2x.t[x],  so_apply: x[s],  play-len: ||moves||,  play-truncate: play-truncate(f;m),  play-item: moves[i]
Lemmas referenced :  nat_properties,  less_than_transitivity1,  less_than_irreflexivity,  ge_wf,  less_than_wf,  int_seg_wf,  strat2play_wf,  win2strat_wf,  false_wf,  le_wf,  decidable__le,  subtract_wf,  not-ge-2,  less-iff-le,  condition-implies-le,  minus-one-mul,  zero-add,  minus-one-mul-top,  minus-add,  minus-minus,  add-associates,  add-swap,  add-commutes,  add_functionality_wrt_le,  add-zero,  le-add-cancel,  le_weakening2,  nat_wf,  simple-game_wf,  decidable__int_equal,  subtype_base_sq,  int_subtype_base,  int_seg_properties,  int_seg_subtype,  int_seg_cases,  eq_int_wf,  le_weakening,  assert_wf,  bnot_wf,  not_wf,  equal-wf-base,  bool_cases,  bool_wf,  bool_subtype_base,  eqtt_to_assert,  assert_of_eq_int,  eqff_to_assert,  iff_transitivity,  iff_weakening_uiff,  assert_of_bnot,  add-is-int-iff,  decidable__lt,  not-lt-2,  le-add-cancel-alt,  lelt_wf,  set_subtype_base,  not-equal-2,  minus-zero,  subtract-add-cancel,  mul-distributes,  mul-commutes,  not-le-2,  le-add-cancel2,  mul_preserves_le,  play-item_wf,  mul-associates,  mul-distributes-right,  zero-mul,  squash_wf,  true_wf,  sg-legal2_wf,  sg-pos_wf,  subtype_rel_self,  iff_weakening_equal,  play-truncate_wf,  equal-wf-T-base,  play-len_wf,  equal_wf,  set_wf,  seq-truncate-item,  seq-item_wf,  seq-len_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation,  cut,  introduction,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesisEquality,  hypothesis,  setElimination,  rename,  intWeakElimination,  natural_numberEquality,  independent_isectElimination,  independent_functionElimination,  voidElimination,  sqequalRule,  lambdaEquality,  dependent_functionElimination,  productElimination,  independent_pairEquality,  axiomEquality,  imageElimination,  imageMemberEquality,  baseClosed,  addEquality,  because_Cache,  dependent_set_memberEquality,  independent_pairFormation,  unionElimination,  applyEquality,  isect_memberEquality,  voidEquality,  intEquality,  minusEquality,  instantiate,  cumulativity,  equalityTransitivity,  equalitySymmetry,  hypothesis_subsumption,  dependentIntersectionElimination,  applyLambdaEquality,  promote_hyp,  impliesFunctionality,  baseApply,  closedConclusion,  multiplyEquality,  universeEquality,  functionEquality,  setEquality,  addLevel,  hyp_replacement,  levelHypothesis

Latex:
\mforall{}g:SimpleGame.  \mforall{}n:\mBbbN{}.  \mforall{}s:win2strat(g;n).  \mforall{}moves:strat2play(g;n;s).
    ((moves[0]  =  InitialPos(g))
    \mwedge{}  (\mforall{}i:\mBbbN{}n  +  1
              ((\mdownarrow{}Legal1(moves[2  *  i];moves[(2  *  i)  +  1]))
              \mwedge{}  (i  <  n
                  {}\mRightarrow{}  ((\mdownarrow{}Legal2(moves[(2  *  i)  +  1];moves[2  *  (i  +  1)]))
                        \mwedge{}  (moves[2  *  (i  +  1)]  =  (s  play-truncate(moves;2  *  (i  +  1)))))))))



Date html generated: 2018_07_25-PM-01_32_57
Last ObjectModification: 2018_06_12-PM-00_30_13

Theory : co-recursion


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