Nuprl Lemma : sqeq-copath2
∀[a,b,n,m:Top].  (if n + 1=m then a else b ~ if n=m - 1 then a else b)
Proof
Definitions occuring in Statement : 
uall: ∀[x:A]. B[x]
, 
top: Top
, 
int_eq: if a=b then c else d
, 
subtract: n - m
, 
add: n + m
, 
natural_number: $n
, 
sqequal: s ~ t
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
true: True
, 
less_than': less_than'(a;b)
, 
le: A ≤ B
, 
top: Top
, 
subtype_rel: A ⊆r B
, 
subtract: n - m
, 
nequal: a ≠ b ∈ T 
, 
not: ¬A
, 
false: False
, 
assert: ↑b
, 
ifthenelse: if b then t else f fi 
, 
bnot: ¬bb
, 
guard: {T}
, 
sq_type: SQType(T)
, 
or: P ∨ Q
, 
prop: ℙ
, 
exists: ∃x:A. B[x]
, 
bfalse: ff
, 
uiff: uiff(P;Q)
, 
btrue: tt
, 
it: ⋅
, 
unit: Unit
, 
bool: 𝔹
, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
, 
uimplies: b supposing a
, 
and: P ∧ Q
, 
has-value: (a)↓
, 
is-exception: is-exception(t)
Lemmas referenced : 
top_wf, 
is-exception_wf, 
has-value_wf_base, 
minus-minus, 
le-add-cancel, 
zero-add, 
add_functionality_wrt_le, 
add-commutes, 
le_antisymmetry_iff, 
minus-one-mul-top, 
add-swap, 
minus-one-mul, 
minus-add, 
base_wf, 
add-associates, 
condition-implies-le, 
not-equal-2, 
add-is-int-iff, 
neg_assert_of_eq_int, 
assert-bnot, 
bool_subtype_base, 
subtype_base_sq, 
bool_cases_sqequal, 
equal_wf, 
eqff_to_assert, 
subtract_wf, 
assert_of_eq_int, 
eqtt_to_assert, 
bool_wf, 
eq_int_wf, 
int-value-type, 
value-type-has-value, 
exception-not-bottom, 
bottom_diverge, 
exception-not-value_1
Rules used in proof : 
isect_memberEquality, 
axiomSqEquality, 
isect_memberFormation, 
because_Cache, 
sqleReflexivity, 
hypothesis, 
hypothesisEquality, 
baseClosed, 
closedConclusion, 
baseApply, 
sqequalRule, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
introduction, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
divergentSqle, 
thin, 
sqleRule, 
cut, 
sqequalSqle, 
natural_numberEquality, 
voidEquality, 
lambdaEquality, 
applyEquality, 
minusEquality, 
addEquality, 
int_eqReduceFalseSq, 
voidElimination, 
independent_functionElimination, 
cumulativity, 
instantiate, 
dependent_functionElimination, 
promote_hyp, 
dependent_pairFormation, 
int_eqReduceTrueSq, 
equalityElimination, 
unionElimination, 
lambdaFormation, 
callbyvalueAdd, 
equalitySymmetry, 
equalityTransitivity, 
independent_isectElimination, 
intEquality, 
productElimination, 
callbyvalueIntEq, 
exceptionSqequal, 
axiomSqleEquality, 
int_eqExceptionCases, 
exceptionInteq, 
addExceptionCases
Latex:
\mforall{}[a,b,n,m:Top].    (if  n  +  1=m  then  a  else  b  \msim{}  if  n=m  -  1  then  a  else  b)
Date html generated:
2019_06_20-PM-01_11_59
Last ObjectModification:
2019_01_02-PM-01_35_34
Theory : co-recursion-2
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