Nuprl Lemma : op-op-cat
∀[C:SmallCategory]. (op-cat(op-cat(C)) = C ∈ SmallCategory)
Proof
Definitions occuring in Statement : 
op-cat: op-cat(C), 
small-category: SmallCategory, 
uall: ∀[x:A]. B[x], 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
small-category: SmallCategory, 
member: t ∈ T, 
implies: P ⇒ Q, 
rev_implies: P ⇐ Q, 
and: P ∧ Q, 
iff: P ⇐⇒ Q, 
guard: {T}, 
uimplies: b supposing a, 
subtype_rel: A ⊆r B, 
true: True, 
prop: ℙ, 
squash: ↓T, 
spreadn: spread4, 
op-cat: op-cat(C), 
all: ∀x:A. B[x]
Lemmas referenced : 
small-category_wf, 
iff_weakening_equal, 
eta_conv, 
true_wf, 
squash_wf, 
equal_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
cut, 
equalitySymmetry, 
sqequalHypSubstitution, 
setElimination, 
thin, 
rename, 
dependent_set_memberEquality_alt, 
hypothesis, 
universeIsType, 
introduction, 
extract_by_obid, 
productEquality, 
independent_pairEquality, 
independent_functionElimination, 
independent_isectElimination, 
baseClosed, 
imageMemberEquality, 
natural_numberEquality, 
because_Cache, 
cumulativity, 
functionEquality, 
universeEquality, 
equalityTransitivity, 
isectElimination, 
imageElimination, 
lambdaEquality, 
instantiate, 
applyEquality, 
functionExtensionality, 
hypothesisEquality, 
dependent_pairEquality, 
sqequalRule, 
productElimination, 
productIsType, 
functionIsType, 
equalityIsType1
Latex:
\mforall{}[C:SmallCategory].  (op-cat(op-cat(C))  =  C)
Date html generated:
2019_10_31-AM-07_24_06
Last ObjectModification:
2018_11_10-AM-11_32_30
Theory : small!categories
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