R3, , . R1 R2:
R3 = R1 R2 = { r | r R1 r R2 } ( Ȼ).
4.
.
:
_4 = [_] [_]
, .
QBE.
- .
_ ( ):
_
_ | |
ü |
_4 . _
: |
R3, , . R1 R2: R3 = R1 R2 = { r | r R1 r R2 } ( Ȼ). 4. . : _4 = [_] [_] , . QBE. - . _ ( ): _
_4 . _
: 2015-10-06; !; : 428 | : : , |