Nuprl Lemma : iff_symmetry
9,38
postcript
pdf
A
,
B
:
. (
A
B
)
(
B
A
)
latex
ProofTree
Definitions
t
T
,
P
Q
,
P
Q
,
P
Q
,
P
Q
,
,
x
:
A
.
B
(
x
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Lemmas
iff
wf
origin
A,B:
. (A 
B) (B A)
A,B:. (A B) (B A)
T Q Q
Q Qx:A. B(x)