Nuprl Lemma : rel_plus_iff
∀[T:Type]. ∀[R:T ⟶ T ⟶ ℙ].  ∀x,z:T.  (x R+ z 
⇐⇒ ∃y:T. ((x (R^*) y) ∧ (y R z)))
Proof
Definitions occuring in Statement : 
rel_plus: R+
, 
rel_star: R^*
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
infix_ap: x f y
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
infix_ap: x f y
, 
prop: ℙ
, 
rev_implies: P 
⇐ Q
, 
exists: ∃x:A. B[x]
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
or: P ∨ Q
, 
cand: A c∧ B
, 
uimplies: b supposing a
, 
subtype_rel: A ⊆r B
Lemmas referenced : 
rel_plus_wf, 
exists_wf, 
and_wf, 
rel_star_wf, 
rel_plus_implies, 
rel_star_weakening, 
rel-plus-rel-star, 
rel-star-rel-plus
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
independent_pairFormation, 
applyEquality, 
cut, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
sqequalRule, 
hypothesis, 
productElimination, 
lambdaEquality, 
functionEquality, 
cumulativity, 
universeEquality, 
dependent_functionElimination, 
independent_functionElimination, 
unionElimination, 
dependent_pairFormation, 
because_Cache, 
independent_isectElimination, 
productEquality
Latex:
\mforall{}[T:Type].  \mforall{}[R:T  {}\mrightarrow{}  T  {}\mrightarrow{}  \mBbbP{}].    \mforall{}x,z:T.    (x  R\msupplus{}  z  \mLeftarrow{}{}\mRightarrow{}  \mexists{}y:T.  ((x  rel\_star(T;  R)  y)  \mwedge{}  (y  R  z)))
Date html generated:
2016_05_14-PM-03_53_47
Last ObjectModification:
2015_12_26-PM-06_56_33
Theory : relations2
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