Nuprl Lemma : grp_inv_inv
∀[g:IGroup]. ∀[a:|g|].  ((~ (~ a)) = a ∈ |g|)
Proof
Definitions occuring in Statement : 
igrp: IGroup, 
grp_inv: ~, 
grp_car: |g|, 
uall: ∀[x:A]. B[x], 
apply: f a, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
igrp: IGroup, 
imon: IMonoid, 
uimplies: b supposing a, 
squash: ↓T, 
prop: ℙ, 
and: P ∧ Q, 
true: True, 
subtype_rel: A ⊆r B, 
guard: {T}, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q, 
implies: P ⇒ Q
Lemmas referenced : 
grp_car_wf, 
igrp_wf, 
grp_op_cancel_l, 
grp_inv_wf, 
equal_wf, 
squash_wf, 
true_wf, 
grp_inverse, 
iff_weakening_equal, 
grp_id_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
hypothesis, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
setElimination, 
rename, 
hypothesisEquality, 
sqequalRule, 
isect_memberEquality, 
axiomEquality, 
because_Cache, 
applyEquality, 
independent_isectElimination, 
lambdaEquality, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
universeEquality, 
productElimination, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
independent_functionElimination
Latex:
\mforall{}[g:IGroup].  \mforall{}[a:|g|].    ((\msim{}  (\msim{}  a))  =  a)
Date html generated:
2017_10_01-AM-08_13_39
Last ObjectModification:
2017_02_28-PM-01_57_54
Theory : groups_1
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