The denotational semantics of R4RS, R5RS and R7RS Scheme (included in the language report) uses the same notation that was used by J. E. Stoy in his book, "Denotational Semantics: the Scott-Strachey approach to programming language theory". This notation includes:
- $s\downarrow k$ for the $k$th element of the sequence $s$
- $\#s$ for the length of sequence $s$
- $s\dagger k$ for dropping of the $k$ first elements of sequence $s$
- $s\S t$ for concatenation of sequences
It seems quite terse, and potentially very cryptic.
I am aware of only one other book that uses this notation -- Christian Queinnec's "Lisp in Small Pieces".
I'd like to know if there are any other introductory books besides Stoy's and Queinnec's which uses it -- and also if it's used in any other works defining denotational semantics of languages, other than Scheme.