# Re: What to call this operator?

From: Vadim Tropashko <vadimtro_invalid_at_yahoo.com>

Date: 1 Jul 2005 11:18:42 -0700

Message-ID: <1120241922.484345.277120_at_z14g2000cwz.googlegroups.com>

Date: 1 Jul 2005 11:18:42 -0700

Message-ID: <1120241922.484345.277120_at_z14g2000cwz.googlegroups.com>

Mikito Harakiri wrote:

*> "there exists employee x and department y such that x works in y
**> AND
**> there exists department y and manager z such that y is led by z"
**>
*

> which can be reduced to

*>
**> "there exists employee x, department y, and manager z
**> such that x works in y and y is led by z"
*

Quantifies are subtle entities. I don't think

"there exists employee x and department y such that x works in y
**AND
**

there exists department v and manager w such that v is led by w"

is logically equivalent to

"there exists employee x, department y, and manager z such that x works in y and y is led by z"

I renamed bind variables in the second half of the first sentence to make this obvious. Received on Fri Jul 01 2005 - 20:18:42 CEST