Nuprl Lemma : lub-com
∀[T:Type]. ∀[R:T ⟶ T ⟶ ℙ].
  ∀[lub:T ⟶ T ⟶ T]
    ∀[a,b:T].  ((lub a b) = (lub b a) ∈ T) supposing ∀[a,b:T].  least-upper-bound(T;x,y.R[x;y];a;b;lub a b) 
  supposing Order(T;x,y.R[x;y])
Proof
Definitions occuring in Statement : 
least-upper-bound: least-upper-bound(T;x,y.R[x; y];a;b;c)
, 
order: Order(T;x,y.R[x; y])
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
so_apply: x[s1;s2]
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
Lemmas referenced : 
least-upper-bound-com, 
uall_wf, 
least-upper-bound_wf, 
order_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
hypothesis, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
because_Cache, 
lemma_by_obid, 
sqequalRule, 
lambdaEquality, 
applyEquality, 
independent_isectElimination, 
isect_memberEquality, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
functionEquality, 
cumulativity, 
universeEquality
Latex:
\mforall{}[T:Type].  \mforall{}[R:T  {}\mrightarrow{}  T  {}\mrightarrow{}  \mBbbP{}].
    \mforall{}[lub:T  {}\mrightarrow{}  T  {}\mrightarrow{}  T]
        \mforall{}[a,b:T].    ((lub  a  b)  =  (lub  b  a)) 
        supposing  \mforall{}[a,b:T].    least-upper-bound(T;x,y.R[x;y];a;b;lub  a  b) 
    supposing  Order(T;x,y.R[x;y])
Date html generated:
2016_05_13-PM-04_18_15
Last ObjectModification:
2015_12_26-AM-11_27_31
Theory : rel_1
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