We study 2- and 3-dimensional digital geometry in the context of almost arbitrary adjacency relations. (Previous authors have based their work on particular adjacency relations). We define a binary digital picture to ...
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We study 2- and 3-dimensional digital geometry in the context of almost arbitrary adjacency relations. (Previous authors have based their work on particular adjacency relations). We define a binary digital picture to be a pair whose components are a set of lattice-points and an adjacency relation on the whole lattice. We show how a wide class of digital pictures have natural “continuous analogs.” This enables us to use methods of continuous topology in studying digital pictures. We are able to prove general results on the connectivity of digital borders, which generalize results that have appeared in the literature. In the 3-dimensional case we consider the possibility of using a uniform relation on the whole lattice. (In the past authors have used different types of adjacency for “object” and “background.”)
Functional programmers often use higher order functions such as map, reduce and filter in writing programs. By giving such higher order functions geometric as well as behavioural interpretation, we use similar techniq...
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We are aiming at a classification of semantical models for Communicating Processes that will enable us to recommend certain models which are just detailed enough for particular applications. But before such an aim can...
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作者：
Raskovsky, Martin R.Essex University
Department Of Computing Science Oxford University Computing Laboratory Programming Research Group United Kingdom
We describe the automatic generation - from the formal denotational semantic specification - of an efficient compiler's code generation phase, producing efficient code for real machines. The method has been succes...
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A method of describing pictures is introduced. The equations, which describe the appearance of a picture, also form a purely functional program which can be used to compute the set of lines necessary to plot the pictu...
A process communicates with its environment and with other processes by syncronized output and input on named channels. The current state of a process is defined by the sequences of messages which have passed along ea...
A process communicates with its environment and with other processes by syncronized output and input on named channels. The current state of a process is defined by the sequences of messages which have passed along each of the channels, and by the sets of messages that may next be passed on each channel. A process satisfies an assertion if the assertion is at all times true of all possible states of the process. We present a calculus for proving that a process satisfies the assertion describing its intended behaviour. The following constructs are axiomatised: output; input; simple recursion; disjoint parallelism; channel renaming, connection and hiding; process chaining; nondeterminism; conditional; alternation; and mutual recursion. The calculus is illustrated by proof of a number of simple buffering protocols.
This paper argues that our recent progress in the development of a sound programming methodology should not lead us to ignore the more difficult aspects of engineering;and that in future we should pay more attention t...
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