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Conference rusure::math

Title:Mathematics at DEC
Moderator:RUSURE::EDP
Created:Mon Feb 03 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2083
Total number of notes:14613

1466.0. "I have always wondered..." by VINO::XIA (In my beginning is my end.) Sat Jun 29 1991 23:36

                                              2
    Does there exist an operator A such that A  = d/dx  ?
    
    Eugene
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1466.1I found such an operator !SMAUG::ABBASISun Jun 30 1991 05:524
    Yes, in the non-Hyber squared Riemann analytic mutli-valued special
    exponential algebra (under the condition it is asymtotic close algebra)
    
    just kidding :-)
1466.2wondering ...HPSRAD::ABIDIIt's a wild worldMon Jul 01 1991 13:323
    
     Is it possible to have a set of points that are all equidistant from
    each other ? In 2-D? In 3-D ?
1466.3GUESS::DERAMOduly notedMon Jul 01 1991 13:449
        The three vertices of an equilateral triangle in R^2, the
        four vertexes of a regular tetrahedron in R^3, etc.
        
        Visualize the first two points as the centers of
        intersecting circles/spheres/n-spheres, and then add each
        new point as the center of another n-sphere of the same
        size.
        
        Dan
1466.4Finite setsCADSYS::COOPERTopher CooperMon Jul 01 1991 13:4518
RE: .2

    In N dimensions you can have a set of N+1 points equidistance from
    each other.

	0-Dimension: degenerate (but it works)
	1-Dimension: the two end-points of a line segement are equidistance
	    from each other
	2-Dimension: the three vertexes of an equilateral triangle are
	    equidistance from each other
	3-Dimension: the four vertexes of a regular tetrahedron are
	    equidistance from each other
	 etc.

    The shape in N dimensions containing N+1 pairwise equidistant points
    is sometimes called the regular N-Simplex.

					Topher
1466.5notes collision :-)GUESS::DERAMOduly notedMon Jul 01 1991 13:460
1466.6CLT::TRACE::GILBERTOwnership ObligatesMon Jul 01 1991 14:224
I recall entering an interesting problem concerning the placement of points
in a plane such that all distances between the points are intergral.

Or was it that all distances were either 1, 2, or 3?
1466.7ELIS::GARSONV+F = E+2Tue Jul 02 1991 06:591
    And for a similar problem see the first problem in 287.0
1466.8ALLVAX::JROTHI know he moves along the piersTue Jul 02 1991 07:5312
          <<< Note 1466.0 by VINO::XIA "In my beginning is my end." >>>
                                              2
>    Does there exist an operator A such that A  = d/dx  ?

    It might be possible to define such an operator with Laplace transforms.
    Fractional derivatives can be defined that way.

    Also, you can sometimes loosely think of linear operators as
    generalizations to continuously many dimensions of matrices transforming
    vectors - that may give a clue as to how to construct such an operator.

    - Jim