Nuprl Lemma : equipollent-int_seg
∀n,m:ℤ.  {n..m-} ~ ℕif n <z m then m - n else 0 fi 
Proof
Definitions occuring in Statement : 
equipollent: A ~ B
, 
int_seg: {i..j-}
, 
ifthenelse: if b then t else f fi 
, 
lt_int: i <z j
, 
all: ∀x:A. B[x]
, 
subtract: n - m
, 
natural_number: $n
, 
int: ℤ
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
implies: P 
⇒ Q
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
ifthenelse: if b then t else f fi 
, 
bfalse: ff
, 
exists: ∃x:A. B[x]
, 
prop: ℙ
, 
or: P ∨ Q
, 
sq_type: SQType(T)
, 
guard: {T}
, 
bnot: ¬bb
, 
assert: ↑b
, 
false: False
, 
not: ¬A
, 
equipollent: A ~ B
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
top: Top
, 
biject: Bij(A;B;f)
, 
inject: Inj(A;B;f)
, 
decidable: Dec(P)
, 
surject: Surj(A;B;f)
Lemmas referenced : 
lt_int_wf, 
bool_wf, 
eqtt_to_assert, 
assert_of_lt_int, 
equipollent_interval, 
eqff_to_assert, 
equal_wf, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
less_than_wf, 
int_seg_properties, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformless_wf, 
itermVar_wf, 
intformle_wf, 
intformnot_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_less_lemma, 
int_term_value_var_lemma, 
int_formula_prop_le_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_wf, 
int_seg_wf, 
decidable__equal_int, 
itermSubtract_wf, 
itermConstant_wf, 
int_term_value_subtract_lemma, 
int_term_value_constant_lemma, 
lelt_wf, 
biject_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
unionElimination, 
equalityElimination, 
equalityTransitivity, 
equalitySymmetry, 
productElimination, 
independent_isectElimination, 
sqequalRule, 
dependent_functionElimination, 
dependent_pairFormation, 
promote_hyp, 
instantiate, 
because_Cache, 
independent_functionElimination, 
voidElimination, 
lambdaEquality, 
setElimination, 
rename, 
natural_numberEquality, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidEquality, 
independent_pairFormation, 
computeAll, 
applyLambdaEquality, 
dependent_set_memberEquality, 
functionExtensionality, 
applyEquality
Latex:
\mforall{}n,m:\mBbbZ{}.    \{n..m\msupminus{}\}  \msim{}  \mBbbN{}if  n  <z  m  then  m  -  n  else  0  fi 
Date html generated:
2017_04_17-AM-09_31_34
Last ObjectModification:
2017_02_27-PM-05_31_43
Theory : equipollence!!cardinality!
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