Nuprl Lemma : seq-tl-len
∀[T:Type]. ∀[s:sequence(T)].  ||seq-tl(s)|| ~ ||s|| - 1 supposing 0 < ||s||
Proof
Definitions occuring in Statement : 
seq-tl: seq-tl(s)
, 
seq-len: ||s||
, 
sequence: sequence(T)
, 
less_than: a < b
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
subtract: n - m
, 
natural_number: $n
, 
universe: Type
, 
sqequal: s ~ t
Definitions unfolded in proof : 
guard: {T}
, 
sq_type: SQType(T)
, 
true: True
, 
less_than': less_than'(a;b)
, 
top: Top
, 
subtype_rel: A ⊆r B
, 
subtract: n - m
, 
uiff: uiff(P;Q)
, 
prop: ℙ
, 
false: False
, 
implies: P 
⇒ Q
, 
rev_implies: P 
⇐ Q
, 
not: ¬A
, 
iff: P 
⇐⇒ Q
, 
or: P ∨ Q
, 
decidable: Dec(P)
, 
all: ∀x:A. B[x]
, 
and: P ∧ Q
, 
le: A ≤ B
, 
pi1: fst(t)
, 
seq-tl: seq-tl(s)
, 
seq-len: ||s||
, 
sequence: sequence(T)
, 
so_apply: x[s]
, 
so_lambda: λ2x.t[x]
, 
nat: ℕ
, 
uimplies: b supposing a
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
Lemmas referenced : 
sequence_wf, 
seq-len_wf, 
less_than_wf, 
le-add-cancel, 
add-zero, 
add_functionality_wrt_le, 
add-commutes, 
add-swap, 
add-associates, 
minus-minus, 
minus-add, 
minus-one-mul-top, 
zero-add, 
minus-one-mul, 
condition-implies-le, 
less-iff-le, 
not-le-2, 
false_wf, 
decidable__le, 
subtract_wf, 
int_subtype_base, 
le_wf, 
set_subtype_base, 
nat_wf, 
subtype_base_sq
Rules used in proof : 
universeEquality, 
sqequalAxiom, 
equalitySymmetry, 
equalityTransitivity, 
minusEquality, 
because_Cache, 
voidEquality, 
isect_memberEquality, 
applyEquality, 
addEquality, 
independent_functionElimination, 
voidElimination, 
lambdaFormation, 
independent_pairFormation, 
unionElimination, 
dependent_functionElimination, 
dependent_set_memberEquality, 
rename, 
setElimination, 
productElimination, 
hypothesisEquality, 
natural_numberEquality, 
lambdaEquality, 
intEquality, 
sqequalRule, 
independent_isectElimination, 
hypothesis, 
cumulativity, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
instantiate, 
thin, 
cut, 
introduction, 
isect_memberFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}[T:Type].  \mforall{}[s:sequence(T)].    ||seq-tl(s)||  \msim{}  ||s||  -  1  supposing  0  <  ||s||
Date html generated:
2018_07_25-PM-01_29_15
Last ObjectModification:
2018_06_17-PM-10_09_26
Theory : arithmetic
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