314 \]

   314 \]

   315 and

   315 and

   316 \[

   316 \[

   317 	(a\times D')\bullet(a\times D'') = a\times (D'\bullet D'') .

   317 	(a\times D')\bullet(a\times D'') = a\times (D'\bullet D'') .

   318 \]

   318 \]

   320 \item

   319 \item

   321 Product morphisms are associative:

   320 Product morphisms are associative:

   322 \[

   321 \[

   323 	(a\times D)\times D' = a\times (D\times D') .

   322 	(a\times D)\times D' = a\times (D\times D') .

   324 \]

   323 \]