Nuprl Lemma : extend_restrict_perm_cancel
∀n:{1...}. ∀p:Sym(n).  (((p.f (n - 1)) = (n - 1) ∈ ℕn) 
⇒ (↑{n - 1}(restrict_perm(p;n - 1)) = p ∈ Sym(n)))
Proof
Definitions occuring in Statement : 
restrict_perm: restrict_perm(p;n)
, 
extend_perm: ↑{n}(p)
, 
sym_grp: Sym(n)
, 
perm_f: p.f
, 
int_upper: {i...}
, 
int_seg: {i..j-}
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
apply: f a
, 
subtract: n - m
, 
natural_number: $n
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
prop: ℙ
, 
uall: ∀[x:A]. B[x]
, 
int_upper: {i...}
, 
sym_grp: Sym(n)
, 
perm: Perm(T)
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
and: P ∧ Q
, 
guard: {T}
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
uimplies: b supposing a
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
not: ¬A
, 
top: Top
, 
restrict_perm: restrict_perm(p;n)
, 
extend_perm: ↑{n}(p)
, 
extend_permf: extend_permf(pf;n)
, 
squash: ↓T
, 
subtype_rel: A ⊆r B
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
ifthenelse: if b then t else f fi 
, 
bfalse: ff
, 
uiff: uiff(P;Q)
, 
sq_type: SQType(T)
, 
bnot: ¬bb
, 
assert: ↑b
, 
true: True
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
le: A ≤ B
, 
inv_funs: InvFuns(A;B;f;g)
, 
compose: f o g
, 
tidentity: Id{T}
, 
identity: Id
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
Lemmas referenced : 
equal_wf, 
int_seg_wf, 
perm_f_wf, 
subtract_wf, 
int_upper_properties, 
decidable__le, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermSubtract_wf, 
itermVar_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_subtract_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
decidable__lt, 
intformless_wf, 
int_formula_prop_less_lemma, 
lelt_wf, 
perm_wf, 
int_upper_wf, 
inv_funs_wf, 
perm_b_wf, 
perm_properties, 
squash_wf, 
true_wf, 
perm_sig_wf, 
mk_perm_eta_rw, 
mk_perm_wf, 
eq_int_wf, 
bool_wf, 
eqff_to_assert, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
neg_assert_of_eq_int, 
iff_weakening_equal, 
equal-wf-T-base, 
assert_wf, 
int_subtype_base, 
int_seg_properties, 
decidable__equal_int_seg, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
bnot_wf, 
not_wf, 
uiff_transitivity, 
eqtt_to_assert, 
assert_of_eq_int, 
iff_transitivity, 
iff_weakening_uiff, 
assert_of_bnot, 
set_subtype_base
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
hypothesis, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
natural_numberEquality, 
setElimination, 
rename, 
because_Cache, 
applyEquality, 
dependent_functionElimination, 
dependent_set_memberEquality, 
independent_pairFormation, 
hypothesisEquality, 
unionElimination, 
independent_isectElimination, 
dependent_pairFormation, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
sqequalRule, 
computeAll, 
equalitySymmetry, 
imageElimination, 
equalityTransitivity, 
universeEquality, 
equalityElimination, 
productElimination, 
promote_hyp, 
instantiate, 
cumulativity, 
independent_functionElimination, 
imageMemberEquality, 
baseClosed, 
functionEquality, 
equalityUniverse, 
levelHypothesis, 
functionExtensionality, 
applyLambdaEquality, 
impliesFunctionality
Latex:
\mforall{}n:\{1...\}.  \mforall{}p:Sym(n).    (((p.f  (n  -  1))  =  (n  -  1))  {}\mRightarrow{}  (\muparrow{}\{n  -  1\}(restrict\_perm(p;n  -  1))  =  p))
Date html generated:
2017_10_01-AM-09_53_34
Last ObjectModification:
2017_03_03-PM-00_48_13
Theory : perms_1
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