Nuprl Lemma : p-compose-inject
∀[A,B,C:Type]. ∀[g:A ⟶ (B + Top)]. ∀[f:B ⟶ (C + Top)].
  (p-inject(A;C;f o g)) supposing (p-inject(B;C;f) and p-inject(A;B;g))
Proof
Definitions occuring in Statement : 
p-inject: p-inject(A;B;f)
, 
p-compose: f o g
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
top: Top
, 
function: x:A ⟶ B[x]
, 
union: left + right
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
p-inject: p-inject(A;B;f)
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
top: Top
, 
guard: {T}
, 
and: P ∧ Q
Lemmas referenced : 
equal_wf, 
do-apply_wf, 
p-compose_wf, 
assert_wf, 
can-apply_wf, 
top_wf, 
subtype_rel_union, 
p-inject_wf, 
can-apply-compose, 
do-apply-compose
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalHypSubstitution, 
lambdaFormation, 
hypothesis, 
extract_by_obid, 
isectElimination, 
thin, 
cumulativity, 
hypothesisEquality, 
functionExtensionality, 
applyEquality, 
independent_isectElimination, 
because_Cache, 
lambdaEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
sqequalRule, 
dependent_functionElimination, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
functionEquality, 
unionEquality, 
universeEquality, 
productElimination, 
independent_functionElimination
Latex:
\mforall{}[A,B,C:Type].  \mforall{}[g:A  {}\mrightarrow{}  (B  +  Top)].  \mforall{}[f:B  {}\mrightarrow{}  (C  +  Top)].
    (p-inject(A;C;f  o  g))  supposing  (p-inject(B;C;f)  and  p-inject(A;B;g))
Date html generated:
2018_05_21-PM-06_32_59
Last ObjectModification:
2017_07_26-PM-04_51_58
Theory : general
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