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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