Nuprl Lemma : iseg-subtype
∀[A,B:Type].  ∀xs,ys:A List.  {xs ≤ ys 
⇒ xs ≤ ys} supposing strong-subtype(A;B)
Proof
Definitions occuring in Statement : 
iseg: l1 ≤ l2
, 
list: T List
, 
strong-subtype: strong-subtype(A;B)
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
guard: {T}
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
universe: Type
Definitions unfolded in proof : 
guard: {T}
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
uimplies: b supposing a
, 
member: t ∈ T
, 
implies: P 
⇒ Q
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
strong-subtype: strong-subtype(A;B)
, 
cand: A c∧ B
, 
iseg: l1 ≤ l2
, 
exists: ∃x:A. B[x]
, 
squash: ↓T
, 
label: ...$L... t
, 
true: True
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
strong-subtype_witness, 
iseg_wf, 
subtype_rel_list, 
strong-subtype_wf, 
list_wf, 
strong-subtype-equal-lists, 
nth_tl_wf, 
length_wf, 
equal_wf, 
nth_tl_append, 
squash_wf, 
true_wf, 
append_wf, 
iff_weakening_equal
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
isect_memberFormation, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
independent_functionElimination, 
hypothesis, 
rename, 
cumulativity, 
applyEquality, 
because_Cache, 
independent_isectElimination, 
productElimination, 
universeEquality, 
equalityTransitivity, 
equalitySymmetry, 
hyp_replacement, 
applyLambdaEquality, 
dependent_pairFormation, 
lambdaEquality, 
imageElimination, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed
Latex:
\mforall{}[A,B:Type].    \mforall{}xs,ys:A  List.    \{xs  \mleq{}  ys  {}\mRightarrow{}  xs  \mleq{}  ys\}  supposing  strong-subtype(A;B)
Date html generated:
2017_04_17-AM-09_00_06
Last ObjectModification:
2017_02_27-PM-05_15_33
Theory : list_1
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