Nuprl Lemma : dl-lt_functionality
∀x,y,x',y':dl-Obj().  ((↑dlo_eq(x;x')) ⇒ (↑dlo_eq(y;y')) ⇒ x ≤ y = x' ≤ y')
Proof
Definitions occuring in Statement : 
dlo_le: a ≤ b, 
dlo_eq: dlo_eq(a;b), 
dl-Obj: dl-Obj(), 
assert: ↑b, 
bool: 𝔹, 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
equal: s = t ∈ T
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
member: t ∈ T, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
squash: ↓T, 
uall: ∀[x:A]. B[x], 
true: True
Lemmas referenced : 
assert-dlo_eq, 
dlo_le_wf, 
istype-assert, 
dlo_eq_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
productElimination, 
independent_functionElimination, 
applyEquality, 
lambdaEquality_alt, 
imageElimination, 
isectElimination, 
because_Cache, 
natural_numberEquality, 
sqequalRule, 
imageMemberEquality, 
baseClosed
Latex:
\mforall{}x,y,x',y':dl-Obj().    ((\muparrow{}dlo\_eq(x;x'))  {}\mRightarrow{}  (\muparrow{}dlo\_eq(y;y'))  {}\mRightarrow{}  x  \mleq{}  y  =  x'  \mleq{}  y')
Date html generated:
2019_10_15-AM-11_44_06
Last ObjectModification:
2019_04_11-PM-02_12_34
Theory : dynamic!logic
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