Nuprl Lemma : seq-cons-item
∀[T:Type]. ∀[a:Top]. ∀[s:sequence(T)]. ∀[i:Top].  (seq-cons(a;s)[i] ~ if (i =z 0) then a else s[i - 1] fi )
Proof
Definitions occuring in Statement : 
seq-cons: seq-cons(a;s)
, 
seq-item: s[i]
, 
sequence: sequence(T)
, 
ifthenelse: if b then t else f fi 
, 
eq_int: (i =z j)
, 
uall: ∀[x:A]. B[x]
, 
top: Top
, 
subtract: n - m
, 
natural_number: $n
, 
universe: Type
, 
sqequal: s ~ t
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
sequence: sequence(T)
, 
seq-item: s[i]
, 
seq-cons: seq-cons(a;s)
, 
pi2: snd(t)
Lemmas referenced : 
top_wf, 
sequence_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalHypSubstitution, 
productElimination, 
thin, 
sqequalRule, 
hypothesis, 
sqequalAxiom, 
extract_by_obid, 
isect_memberEquality, 
isectElimination, 
hypothesisEquality, 
because_Cache, 
universeEquality
Latex:
\mforall{}[T:Type].  \mforall{}[a:Top].  \mforall{}[s:sequence(T)].  \mforall{}[i:Top].
    (seq-cons(a;s)[i]  \msim{}  if  (i  =\msubz{}  0)  then  a  else  s[i  -  1]  fi  )
Date html generated:
2018_07_25-PM-01_29_01
Last ObjectModification:
2018_06_12-PM-10_29_47
Theory : arithmetic
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