Nuprl Lemma : sign-flip
∀[n:ℕ]. ∀[u,v:ℕn].  permutation-sign(n;(u, v)) = (-1) ∈ ℤ supposing ¬(u = v ∈ ℤ)
Proof
Definitions occuring in Statement : 
permutation-sign: permutation-sign(n;f)
, 
flip: (i, j)
, 
int_seg: {i..j-}
, 
nat: ℕ
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
not: ¬A
, 
minus: -n
, 
natural_number: $n
, 
int: ℤ
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
int_seg: {i..j-}
, 
subtype_rel: A ⊆r B
, 
true: True
, 
compose: f o g
, 
squash: ↓T
, 
uimplies: b supposing a
, 
prop: ℙ
, 
nat: ℕ
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
Lemmas referenced : 
not_wf, 
permutation-sign-id, 
int_subtype_base, 
equal-wf-base, 
flip_wf, 
nat_wf, 
permutation-sign_wf, 
true_wf, 
squash_wf, 
equal_wf, 
inject_wf, 
int_seg_wf, 
identity-injection, 
permutation-sign-flip
Rules used in proof : 
minusEquality, 
closedConclusion, 
baseApply, 
setEquality, 
baseClosed, 
imageMemberEquality, 
functionEquality, 
intEquality, 
universeEquality, 
equalityTransitivity, 
imageElimination, 
sqequalRule, 
equalitySymmetry, 
hyp_replacement, 
independent_isectElimination, 
applyEquality, 
functionExtensionality, 
because_Cache, 
lambdaEquality, 
dependent_set_memberEquality, 
rename, 
setElimination, 
natural_numberEquality, 
hypothesisEquality, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
hypothesis, 
isect_memberFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
extract_by_obid, 
introduction, 
cut
Latex:
\mforall{}[n:\mBbbN{}].  \mforall{}[u,v:\mBbbN{}n].    permutation-sign(n;(u,  v))  =  (-1)  supposing  \mneg{}(u  =  v)
Date html generated:
2018_05_21-PM-00_59_01
Last ObjectModification:
2017_12_10-PM-11_26_58
Theory : num_thy_1
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