Nuprl Lemma : strong-subtype-deq
∀[A,B:Type]. ∀[d:EqDecider(B)].  d ∈ EqDecider(A) supposing strong-subtype(A;B)
Proof
Definitions occuring in Statement : 
deq: EqDecider(T)
, 
strong-subtype: strong-subtype(A;B)
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
implies: P 
⇒ Q
, 
guard: {T}
, 
strong-subtype: strong-subtype(A;B)
, 
cand: A c∧ B
, 
deq: EqDecider(T)
, 
subtype_rel: A ⊆r B
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
prop: ℙ
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
strong-subtype-implies, 
subtype_rel_dep_function, 
bool_wf, 
subtype_rel_self, 
equal_wf, 
assert_wf, 
all_wf, 
iff_wf, 
strong-subtype_wf, 
deq_wf, 
equal_functionality_wrt_subtype_rel2
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
independent_functionElimination, 
hypothesis, 
productElimination, 
setElimination, 
rename, 
dependent_set_memberEquality, 
applyEquality, 
sqequalRule, 
lambdaEquality, 
functionEquality, 
independent_isectElimination, 
lambdaFormation, 
because_Cache, 
independent_pairFormation, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
isect_memberEquality, 
universeEquality, 
dependent_functionElimination
Latex:
\mforall{}[A,B:Type].  \mforall{}[d:EqDecider(B)].    d  \mmember{}  EqDecider(A)  supposing  strong-subtype(A;B)
Date html generated:
2016_05_14-AM-06_06_49
Last ObjectModification:
2015_12_26-AM-11_46_54
Theory : equality!deciders
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