Toy Languages and Free Imaginations

Context - Free Languages and

Free Grammars and Languages

Floyd’s Operator Precedence languages (OPLs) were originally introduced to support deterministic parsing of programming languages [11]; then, interest in them decayed for several decades, probably due to the advent of more expressive grammars, such as LR ones which also allow for efficient deterministic parsing. Recently, however, we renewed our interest in this family of languages on the basis...

Context - Free Languages and PushdownAutomataJean -

Circuits and Context-Free Languages

Simpler proofs that DAuxPDA-TIME(polynomial) equals LOGDCFL and that SAC 1 equals LOGCFL are given which avoid Sudborough's multi-head au-tomata Sud78]. The rst characterization of LOGDCFL in terms of polynomial proof-tree-size is obtained, using circuits built from the multiplex select gates of FLR96]. The classes L and NC 1 are also characterized by polynomial size such circuits: \self-simila...

Generational research: between historical and sociological imaginations

In an overview of the history of post war British sociological research Mike Savage traces a transition from what he describes as a ‘gentlemanly sociology’ – normative in intention drawing on narrative and secondary sources – to a technical and empirical project employing the new methods of the interview and the survey. The latter, he suggests, abandoned an evolutionary project of relating past...