Nuprl Lemma : inject-subtype
∀[C,A:Type].  ∀[B:Type]. ∀[f:A ⟶ B].  Inj(C;B;f) supposing Inj(A;B;f) supposing strong-subtype(C;A)
Proof
Definitions occuring in Statement : 
strong-subtype: strong-subtype(A;B)
, 
inject: Inj(A;B;f)
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
inject: Inj(A;B;f)
, 
all: ∀x:A. B[x]
, 
subtype_rel: A ⊆r B
, 
strong-subtype: strong-subtype(A;B)
, 
cand: A c∧ B
, 
implies: P 
⇒ Q
, 
label: ...$L... t
, 
guard: {T}
, 
prop: ℙ
Lemmas referenced : 
strong-subtype-eq1, 
inject_wf, 
strong-subtype_wf, 
istype-universe
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
sqequalHypSubstitution, 
lambdaFormation_alt, 
hypothesis, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
applyEquality, 
productElimination, 
sqequalRule, 
independent_functionElimination, 
extract_by_obid, 
isectElimination, 
because_Cache, 
independent_isectElimination, 
equalityIstype, 
universeIsType, 
lambdaEquality_alt, 
axiomEquality, 
functionIsTypeImplies, 
inhabitedIsType, 
isect_memberEquality_alt, 
isectIsTypeImplies, 
functionIsType, 
instantiate, 
universeEquality
Latex:
\mforall{}[C,A:Type].    \mforall{}[B:Type].  \mforall{}[f:A  {}\mrightarrow{}  B].    Inj(C;B;f)  supposing  Inj(A;B;f)  supposing  strong-subtype(C;A)
Date html generated:
2020_05_19-PM-09_36_21
Last ObjectModification:
2020_01_25-PM-08_00_58
Theory : subtype_1
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