Concrete Data Structure
(CDS) A model of programming language terms developed in the context of constructing fully abstract semantics for sequential languages.
A CDS is a 4-tuple (C,V,E,|-) where C is a cell, V is a value, E is an event and |- is an "enabling relation".
An event is a cell and a value.
A cell C is "enabled" by a set of events S if S |- C.
A state is a set of events which are consistent in that the values they give for any cell are all equal.
Every cell in a state is enabled.
[G. Berry, P.-L. Curien, "Theory and practice of sequential algorithms: the kernel of applicative language CDS", Algebraic methods in semantics, CUP 1985].