Nuprl Lemma : fset-pair-symmetry
∀[T:Type]. ∀[a,b:T].  ({a,b} = {b,a} ∈ fset(T))
Proof
Definitions occuring in Statement : 
fset-pair: {a,b}
, 
fset: fset(T)
, 
uall: ∀[x:A]. B[x]
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
rev_implies: P 
⇐ Q
, 
false: False
, 
prop: ℙ
, 
guard: {T}
, 
or: P ∨ Q
, 
and: P ∧ Q
, 
iff: P 
⇐⇒ Q
, 
set-equal: set-equal(T;x;y)
, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
, 
uimplies: b supposing a
, 
so_apply: x[s1;s2]
, 
so_lambda: λ2x y.t[x; y]
, 
fset: fset(T)
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
fset-pair: {a,b}
Lemmas referenced : 
iff_wf, 
l_member_wf, 
nil_member, 
cons_member, 
or_wf, 
equal_wf, 
false_wf, 
nil_wf, 
cons_wf, 
set-equal-equiv, 
list_wf, 
set-equal_wf, 
quotient-member-eq
Rules used in proof : 
orFunctionality, 
productElimination, 
addLevel, 
voidElimination, 
inlFormation, 
inrFormation, 
unionElimination, 
independent_pairFormation, 
lambdaFormation, 
axiomEquality, 
isect_memberEquality, 
independent_functionElimination, 
dependent_functionElimination, 
independent_isectElimination, 
hypothesis, 
hypothesisEquality, 
cumulativity, 
lambdaEquality, 
because_Cache, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
cut, 
introduction, 
isect_memberFormation, 
computationStep, 
sqequalTransitivity, 
sqequalReflexivity, 
sqequalRule, 
sqequalSubstitution
Latex:
\mforall{}[T:Type].  \mforall{}[a,b:T].    (\{a,b\}  =  \{b,a\})
Date html generated:
2017_02_20-AM-10_48_42
Last ObjectModification:
2017_02_10-PM-02_29_32
Theory : finite!sets
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