Nuprl Lemma : decidable__implies
∀[P:ℙ]. ∀[Q:⋂p:P. ℙ].  (Dec(P) 
⇒ (P 
⇒ Dec(Q)) 
⇒ Dec(P 
⇒ Q))
Proof
Definitions occuring in Statement : 
decidable: Dec(P)
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
implies: P 
⇒ Q
, 
isect: ⋂x:A. B[x]
Definitions unfolded in proof : 
decidable: Dec(P)
, 
uall: ∀[x:A]. B[x]
, 
implies: P 
⇒ Q
, 
or: P ∨ Q
, 
member: t ∈ T
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
not: ¬A
, 
false: False
Lemmas referenced : 
not_wf, 
or_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
Error :isect_memberFormation_alt, 
lambdaFormation, 
sqequalHypSubstitution, 
unionElimination, 
thin, 
independent_functionElimination, 
hypothesis, 
inlFormation, 
hypothesisEquality, 
cut, 
introduction, 
extract_by_obid, 
isectElimination, 
functionEquality, 
applyEquality, 
lambdaEquality, 
rename, 
equalityTransitivity, 
equalitySymmetry, 
isectEquality, 
cumulativity, 
universeEquality, 
inrFormation, 
voidElimination, 
because_Cache, 
Error :isectIsType, 
Error :universeIsType, 
Error :inhabitedIsType
Latex:
\mforall{}[P:\mBbbP{}].  \mforall{}[Q:\mcap{}p:P.  \mBbbP{}].    (Dec(P)  {}\mRightarrow{}  (P  {}\mRightarrow{}  Dec(Q))  {}\mRightarrow{}  Dec(P  {}\mRightarrow{}  Q))
Date html generated:
2019_06_20-AM-11_14_58
Last ObjectModification:
2018_09_26-AM-10_42_05
Theory : core_2
Home
Index