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Details of Grant 

EPSRC Reference: GR/L77171/01
Title: APPLICATIONS OF EXACT REAL NUMBER COMPUTATION
Principal Investigator: Edalat, Professor A
Other Investigators:
Researcher Co-Investigators:
Project Partners:
Department: Computing
Organisation: Imperial College London
Scheme: Standard Research (Pre-FEC)
Starts: 21 July 1997 Ends: 20 July 1998 Value (£): 3,400
EPSRC Research Topic Classifications:
Fundamentals of Computing
EPSRC Industrial Sector Classifications:
No relevance to Underpinning Sectors
Related Grants:
Panel History:  
Summary on Grant Application Form
In our new framework for exact real arithmetic, an extended real number is represented by a shrinking sequence of nested national intervals, encoded by an infinite composition of lfts. The first lft locates the position of the real number under computation in an interval. The remaining lft's have non-negative integer coefficients and give successive refinement of the first interval up to any desired accuracy. All elementary functions are expressed, using the theory of continued fractions and Pad+ approximants, in terms of composition of lft's with two arguments. Apart from elementary functions, we need to be able compute various other functions and operations. We propose to use and adopt various classical results and techniques of interval arithmetic in order to work out new algorithms and techniques for:(i) Efficient handling of comparison, maximum/minimum, absolute value, and definition by cases, (ii) Calculation of the limit of a given convergent sequence of real numbers. The problem is to merge an infinite sequence of infinite streams describing real numbers to one infinite stream describing their limit.(iii) Using the results of the above to compute the value of an infinite sum, the integral of a function as the limit of the sequence of lower or upper Darboux sums, and the Taylor series as a function.
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Organisation Website: http://www.imperial.ac.uk