Nuprl Lemma : iff_symmetry
13,42
postcript
pdf
A
,
B
:
. (
A
B
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(
B
A
)
latex
Up
core
2
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core
2
Definitions
t
T
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P
Q
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P
Q
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P
&
Q
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P
Q
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x
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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 Qx:A. B(x)