Nuprl Lemma : pigeon-hole-implies2
∀n:ℕ
  ∀[m:ℕ]
    ∀f:ℕn ⟶ ℕm. ∀g:ℕn ⟶ ℕm. ∃i:ℕn. (∃j:ℕn [((f i) = (g j) ∈ ℤ)]) supposing Inj(ℕn;ℕm;g) supposing Inj(ℕn;ℕm;f) 
    supposing m < 2 * n
Proof
Definitions occuring in Statement : 
inject: Inj(A;B;f)
, 
int_seg: {i..j-}
, 
nat: ℕ
, 
less_than: a < b
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
sq_exists: ∃x:A [B[x]]
, 
exists: ∃x:A. B[x]
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
multiply: n * m
, 
natural_number: $n
, 
int: ℤ
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
uall: ∀[x:A]. B[x]
, 
uimplies: b supposing a
, 
member: t ∈ T
, 
nat: ℕ
, 
inject: Inj(A;B;f)
, 
implies: P 
⇒ Q
, 
prop: ℙ
, 
ge: i ≥ j 
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
not: ¬A
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
top: Top
, 
and: P ∧ Q
, 
int_seg: {i..j-}
, 
less_than: a < b
, 
less_than': less_than'(a;b)
, 
true: True
, 
squash: ↓T
, 
lelt: i ≤ j < k
, 
guard: {T}
, 
sq_exists: ∃x:A [B[x]]
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
subtype_rel: A ⊆r B
, 
bfalse: ff
, 
sq_type: SQType(T)
, 
bnot: ¬bb
, 
ifthenelse: if b then t else f fi 
, 
assert: ↑b
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
Lemmas referenced : 
member-less_than, 
equal_wf, 
int_seg_wf, 
pigeon-hole-implies-ext, 
nat_properties, 
decidable__le, 
full-omega-unsat, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermMultiply_wf, 
itermVar_wf, 
intformless_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_mul_lemma, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
le_wf, 
less_than_wf, 
lelt_wf, 
subtract_wf, 
int_seg_properties, 
itermSubtract_wf, 
int_term_value_subtract_lemma, 
decidable__lt, 
lt_int_wf, 
bool_wf, 
eqtt_to_assert, 
assert_of_lt_int, 
top_wf, 
sq_stable__equal, 
eqff_to_assert, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
inject_wf, 
nat_wf, 
decidable__equal_int, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
sq_exists_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
isect_memberFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
setElimination, 
rename, 
hypothesisEquality, 
hypothesis, 
multiplyEquality, 
natural_numberEquality, 
independent_isectElimination, 
sqequalRule, 
lambdaEquality, 
dependent_functionElimination, 
axiomEquality, 
because_Cache, 
applyEquality, 
dependent_set_memberEquality, 
unionElimination, 
approximateComputation, 
independent_functionElimination, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
independent_pairFormation, 
lessCases, 
baseClosed, 
equalityTransitivity, 
equalitySymmetry, 
imageMemberEquality, 
axiomSqEquality, 
imageElimination, 
productElimination, 
functionExtensionality, 
equalityElimination, 
promote_hyp, 
instantiate, 
cumulativity, 
functionEquality, 
applyLambdaEquality, 
dependent_set_memberFormation
Latex:
\mforall{}n:\mBbbN{}
    \mforall{}[m:\mBbbN{}]
        \mforall{}f:\mBbbN{}n  {}\mrightarrow{}  \mBbbN{}m
            \mforall{}g:\mBbbN{}n  {}\mrightarrow{}  \mBbbN{}m.  \mexists{}i:\mBbbN{}n.  (\mexists{}j:\mBbbN{}n  [((f  i)  =  (g  j))])  supposing  Inj(\mBbbN{}n;\mBbbN{}m;g)  supposing  Inj(\mBbbN{}n;\mBbbN{}m;f) 
        supposing  m  <  2  *  n
Date html generated:
2019_06_20-PM-01_32_21
Last ObjectModification:
2018_08_20-PM-09_32_22
Theory : list_1
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