Consider the following definitions: 1. Denotational semantics can be considered as relation between syntax and mathematical objects (the meaning of the syntax). 2. Operational semantics can be considered as set of rules for performing computation. Question 1 Applying these definitions in a Haskell context can I say that the lambda calculus provides both the operational and denotational semantics for Haskell programs at value level for definition and evaluations. Question 2 Does it make sense to use these definitions at type level? If so, what exactly do they represent? Thanks, Pat This message has been scanned for content and viruses by the DIT Information Services E-Mail Scanning Service, and is believed to be clean. http://www.dit.ie