Nuprl Lemma : bfs-reduce-strong-subtype-iff
∀[K:RngSig]. ∀[S,T:Type].
  ∀[as,bs:basic-formal-sum(K;S)].  (bfs-reduce(K;T;as;bs) ⇐⇒ bfs-reduce(K;S;as;bs)) supposing strong-subtype(S;T)
Proof
Definitions occuring in Statement : 
bfs-reduce: bfs-reduce(K;S;as;bs), 
basic-formal-sum: basic-formal-sum(K;S), 
strong-subtype: strong-subtype(A;B), 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
iff: P ⇐⇒ Q, 
universe: Type, 
rng_sig: RngSig
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
uimplies: b supposing a, 
member: t ∈ T, 
implies: P ⇒ Q, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
subtype_rel: A ⊆r B, 
strong-subtype: strong-subtype(A;B), 
cand: A c∧ B, 
prop: ℙ, 
rev_implies: P ⇐ Q, 
guard: {T}
Lemmas referenced : 
strong-subtype_witness, 
bfs-reduce-strong-subtype, 
bfs-reduce_wf, 
basic-formal-sum-subtype, 
bfs-reduce-subtype1, 
basic-formal-sum_wf, 
strong-subtype_wf, 
istype-universe, 
rng_sig_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
independent_functionElimination, 
hypothesis, 
rename, 
independent_pairFormation, 
lambdaFormation_alt, 
independent_isectElimination, 
universeIsType, 
applyEquality, 
productElimination, 
sqequalRule, 
inhabitedIsType, 
instantiate, 
universeEquality
Latex:
\mforall{}[K:RngSig].  \mforall{}[S,T:Type].
    \mforall{}[as,bs:basic-formal-sum(K;S)].    (bfs-reduce(K;T;as;bs)  \mLeftarrow{}{}\mRightarrow{}  bfs-reduce(K;S;as;bs)) 
    supposing  strong-subtype(S;T)
Date html generated:
2019_10_31-AM-06_29_24
Last ObjectModification:
2019_08_15-PM-04_45_27
Theory : linear!algebra
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