Nuprl Lemma : cat-comp-assoc
∀[C:SmallCategory]
  ∀x,y,z,w:cat-ob(C). ∀f:cat-arrow(C) x y. ∀g:cat-arrow(C) y z. ∀h:cat-arrow(C) z w.
    ((cat-comp(C) x z w (cat-comp(C) x y z f g) h) = (cat-comp(C) x y w f (cat-comp(C) y z w g h)) ∈ (cat-arrow(C) x w))
Proof
Definitions occuring in Statement : 
cat-comp: cat-comp(C)
, 
cat-arrow: cat-arrow(C)
, 
cat-ob: cat-ob(C)
, 
small-category: SmallCategory
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
apply: f a
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
all: ∀x:A. B[x]
, 
small-category: SmallCategory
, 
cat-arrow: cat-arrow(C)
, 
pi2: snd(t)
, 
pi1: fst(t)
, 
cat-ob: cat-ob(C)
, 
cat-comp: cat-comp(C)
, 
spreadn: spread4, 
and: P ∧ Q
, 
squash: ↓T
, 
prop: ℙ
, 
true: True
, 
subtype_rel: A ⊆r B
, 
uimplies: b supposing a
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
Lemmas referenced : 
equal_wf, 
squash_wf, 
true_wf, 
iff_weakening_equal, 
cat-arrow_wf, 
cat-ob_wf, 
small-category_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
lambdaFormation, 
sqequalHypSubstitution, 
setElimination, 
thin, 
rename, 
productElimination, 
sqequalRule, 
applyEquality, 
lambdaEquality, 
imageElimination, 
extract_by_obid, 
isectElimination, 
hypothesisEquality, 
equalityTransitivity, 
hypothesis, 
equalitySymmetry, 
universeEquality, 
functionExtensionality, 
cumulativity, 
dependent_functionElimination, 
because_Cache, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
independent_isectElimination, 
independent_functionElimination, 
axiomEquality
Latex:
\mforall{}[C:SmallCategory]
    \mforall{}x,y,z,w:cat-ob(C).  \mforall{}f:cat-arrow(C)  x  y.  \mforall{}g:cat-arrow(C)  y  z.  \mforall{}h:cat-arrow(C)  z  w.
        ((cat-comp(C)  x  z  w  (cat-comp(C)  x  y  z  f  g)  h)  =  (cat-comp(C)  x  y  w  f  (cat-comp(C)  y  z  w  g  h)))
Date html generated:
2020_05_20-AM-07_49_57
Last ObjectModification:
2017_07_28-AM-09_18_59
Theory : small!categories
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