Nuprl Lemma : combination-decomp
∀[A:Type]. ∀[n:ℕ+]. ∀[L:Combination(n;A)].  {(hd(L) ∈ A) ∧ (tl(L) ∈ Combination(n - 1;{a:A| ¬(a = hd(L) ∈ A)} ))}
Proof
Definitions occuring in Statement : 
combination: Combination(n;T)
, 
hd: hd(l)
, 
tl: tl(l)
, 
nat_plus: ℕ+
, 
uall: ∀[x:A]. B[x]
, 
guard: {T}
, 
not: ¬A
, 
and: P ∧ Q
, 
member: t ∈ T
, 
set: {x:A| B[x]} 
, 
subtract: n - m
, 
natural_number: $n
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
combination: Combination(n;T)
, 
all: ∀x:A. B[x]
, 
or: P ∨ Q
, 
guard: {T}
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
nat_plus: ℕ+
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
implies: P 
⇒ Q
, 
not: ¬A
, 
top: Top
, 
prop: ℙ
, 
cons: [a / b]
, 
uiff: uiff(P;Q)
, 
nat: ℕ
, 
ge: i ≥ j 
, 
subtype_rel: A ⊆r B
, 
colength: colength(L)
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
decidable: Dec(P)
, 
nil: []
, 
it: ⋅
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
sq_type: SQType(T)
, 
less_than: a < b
, 
squash: ↓T
, 
less_than': less_than'(a;b)
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
cand: A c∧ B
Lemmas referenced : 
list-cases, 
reduce_tl_nil_lemma, 
length_of_nil_lemma, 
hd_wf, 
nil_wf, 
nat_plus_properties, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformeq_wf, 
itermConstant_wf, 
itermVar_wf, 
intformless_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_eq_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
product_subtype_list, 
reduce_hd_cons_lemma, 
reduce_tl_cons_lemma, 
length_of_cons_lemma, 
combination_wf, 
nat_plus_wf, 
no_repeats_cons, 
nat_properties, 
intformle_wf, 
int_formula_prop_le_lemma, 
ge_wf, 
less_than_wf, 
not_wf, 
l_member_wf, 
equal-wf-T-base, 
nat_wf, 
colength_wf_list, 
less_than_transitivity1, 
less_than_irreflexivity, 
equal_wf, 
spread_cons_lemma, 
itermAdd_wf, 
int_term_value_add_lemma, 
decidable__le, 
intformnot_wf, 
int_formula_prop_not_lemma, 
le_wf, 
subtract_wf, 
itermSubtract_wf, 
int_term_value_subtract_lemma, 
subtype_base_sq, 
set_subtype_base, 
int_subtype_base, 
decidable__equal_int, 
cons_wf, 
cons_member, 
list_wf, 
no_repeats-subtype, 
add-is-int-iff, 
false_wf, 
no_repeats_wf, 
length_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalHypSubstitution, 
setElimination, 
thin, 
rename, 
hypothesisEquality, 
extract_by_obid, 
isectElimination, 
hypothesis, 
dependent_functionElimination, 
unionElimination, 
sqequalRule, 
independent_pairFormation, 
productElimination, 
cumulativity, 
because_Cache, 
independent_isectElimination, 
natural_numberEquality, 
dependent_pairFormation, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
computeAll, 
promote_hyp, 
hypothesis_subsumption, 
independent_pairEquality, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
universeEquality, 
lambdaFormation, 
intWeakElimination, 
independent_functionElimination, 
applyEquality, 
setEquality, 
applyLambdaEquality, 
dependent_set_memberEquality, 
addEquality, 
baseClosed, 
instantiate, 
imageElimination, 
inlFormation, 
hyp_replacement, 
inrFormation, 
pointwiseFunctionality, 
baseApply, 
closedConclusion, 
productEquality
Latex:
\mforall{}[A:Type].  \mforall{}[n:\mBbbN{}\msupplus{}].  \mforall{}[L:Combination(n;A)].
    \{(hd(L)  \mmember{}  A)  \mwedge{}  (tl(L)  \mmember{}  Combination(n  -  1;\{a:A|  \mneg{}(a  =  hd(L))\}  ))\}
Date html generated:
2018_05_21-PM-08_08_25
Last ObjectModification:
2017_07_26-PM-05_44_07
Theory : general
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