Nuprl Lemma : least-equiv-induction
∀[A:Type]. ∀[P:A ⟶ ℙ]. ∀[R:A ⟶ A ⟶ ℙ].
  ((∀x,y:A.  ((x R y) 
⇒ (P[x] 
⇐⇒ P[y]))) 
⇒ (∀x,y:A.  ((x least-equiv(A;R) y) 
⇒ P[x] 
⇒ P[y])))
Proof
Definitions occuring in Statement : 
least-equiv: least-equiv(A;R)
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
infix_ap: x f y
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
implies: P 
⇒ Q
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
, 
infix_ap: x f y
, 
least-equiv: least-equiv(A;R)
, 
transitive-reflexive-closure: R^*
, 
or: P ∨ Q
, 
prop: ℙ
, 
and: P ∧ Q
, 
member: t ∈ T
, 
so_apply: x[s]
, 
so_lambda: λ2x.t[x]
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
and_wf, 
equal_wf, 
transitive-closure-induction, 
or_wf, 
infix_ap_wf, 
least-equiv_wf, 
all_wf, 
iff_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
sqequalHypSubstitution, 
sqequalRule, 
unionElimination, 
thin, 
cut, 
hypothesis, 
addLevel, 
hyp_replacement, 
equalitySymmetry, 
dependent_set_memberEquality, 
independent_pairFormation, 
hypothesisEquality, 
introduction, 
extract_by_obid, 
isectElimination, 
applyLambdaEquality, 
setElimination, 
rename, 
productElimination, 
applyEquality, 
levelHypothesis, 
lambdaEquality, 
independent_functionElimination, 
instantiate, 
cumulativity, 
universeEquality, 
because_Cache, 
dependent_functionElimination, 
functionEquality
Latex:
\mforall{}[A:Type].  \mforall{}[P:A  {}\mrightarrow{}  \mBbbP{}].  \mforall{}[R:A  {}\mrightarrow{}  A  {}\mrightarrow{}  \mBbbP{}].
    ((\mforall{}x,y:A.    ((x  R  y)  {}\mRightarrow{}  (P[x]  \mLeftarrow{}{}\mRightarrow{}  P[y])))  {}\mRightarrow{}  (\mforall{}x,y:A.    ((x  least-equiv(A;R)  y)  {}\mRightarrow{}  P[x]  {}\mRightarrow{}  P[y])))
Date html generated:
2018_05_21-PM-00_52_06
Last ObjectModification:
2018_05_04-AM-10_21_29
Theory : relations2
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