Presentation Logic vs. Business Logic

How do you know which logic goes in which tier? There is no absolute rule, but a good rule of thumb is the following: If it's a piece of logic that might be executed no matter what type of UI (Web or Windows), it probably should be coded in the middle tier.

http://www.informit.com/articles/article.aspx?p=22679&seqNum=3

The EXEC CICS RECEIVE and EXEC CICS SEND MAP commands are part of the transaction’s presentation logic, while the EXEC CICS READ UPDATE and EXEC CICS REWRITE commands are part of the business logic.

http://publib.boulder.ibm.com/infocenter/cicsts/v2r3/index.jsp?topic=/com.ibm.cics.ts23.doc/dfhp3/dfhp3pu.htm

The part of an application program that performs the required data processing of the business. It refers to the routines that perform the data entry, update, query and report processing, and more specifically to the processing that takes place behind the scenes rather than the presentation logic required to display the data on the screen (GUI processing).

 http://www.pcmag.com/encyclopedia_term/0,1233,t=business+logic&i=39074,00.asp

[S]ome duplication, especially for validation purposes should exist in the client as well. Such rules should be reinforced by the business layer.

http://www.codeproject.com/Articles/10746/Dude-where-s-my-business-logic