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- The statement
`x`is prime : <=>`y`not |`x``y`does not occur on left side. - The statement
`x`is a*divisor*of`a`*`y`, if`x`*`z`=`a`*`y`, for some`z`.*not*a definition, because on the left hand side of the formula`x`is a divisor of`a`*`y`<=>**exists**`z`:`x`*`z`=`a`*`y`.`a`*`y`appears where only a variable is allowed.

*Beware of bogus definitions!*

Author: Wolfgang Schreiner

Last Modification: October 14, 1999