Nuprl Lemma : p-conditional-to-p-first
11,40
postcript
pdf
A
,
B
:Type,
f
,
g
:(
A
(
B
+ Top)). [
f
?
g
] = p-first([
f
;
g
])
A
(
B
+ Top)
latex
ProofTree
Definitions
Top
,
left
+
right
,
x
:
A
B
(
x
)
,
type
List
,
[]
,
t
T
,
A
List
,
s
=
t
,
x
:
A
.
B
(
x
)
,
[
car
/
cdr
]
,
p-first(
L
)
,
Type
,
[
f
?
g
]
,
f
(
a
)
,
inr
x
,
P
Q
,
can-apply(
f
;
x
)
Lemmas
p-conditional
wf
,
p-first
wf
,
top
wf
origin
A, B:Type, f, g:(A
(B + Top)). [f?g] = p-first([f; g]) 
A(B + Top)
A, B:Type, f, g:(A(B + Top)). [f?g] = p-first([f; g]) A(B + Top)
B(x) T
x:A. B(x)
Q