Nuprl Lemma : name_eq_symmetry
∀[x,y:Name].  (name_eq(x;y) ~ name_eq(y;x))
Proof
Definitions occuring in Statement : 
name_eq: name_eq(x;y), 
name: Name, 
uall: ∀[x:A]. B[x], 
sqequal: s ~ t
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
uimplies: b supposing a, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
implies: P ⇒ Q, 
prop: ℙ, 
rev_implies: P ⇐ Q, 
uiff: uiff(P;Q), 
sq_type: SQType(T), 
all: ∀x:A. B[x], 
guard: {T}
Lemmas referenced : 
subtype_base_sq, 
bool_wf, 
bool_subtype_base, 
iff_imp_equal_bool, 
name_eq_wf, 
equal_wf, 
name_wf, 
assert-name_eq, 
assert_wf, 
iff_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
thin, 
instantiate, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
cumulativity, 
hypothesis, 
independent_isectElimination, 
hypothesisEquality, 
independent_pairFormation, 
lambdaFormation, 
equalitySymmetry, 
addLevel, 
productElimination, 
impliesFunctionality, 
because_Cache, 
dependent_functionElimination, 
equalityTransitivity, 
independent_functionElimination, 
sqequalAxiom, 
sqequalRule, 
isect_memberEquality
Latex:
\mforall{}[x,y:Name].    (name\_eq(x;y)  \msim{}  name\_eq(y;x))
Date html generated:
2016_05_14-PM-03_34_31
Last ObjectModification:
2015_12_26-PM-06_00_11
Theory : decidable!equality
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