@vv Sorry, the code returns me the error

Error, invalid proc termination
 

What do you think about this code?  GKLS.mw

I reiterate my gratitude for your help.

@Carl Love  Many thanks for your reply,

I have coded this GKLS.mw  to compute the centers (I think that the calculus of the radii is easy).

However, CreaParam(2, 15, .6)

Return me 2 centers instead of 15. Can you help me please?

@vv  Thanks for your answer, it sounds good!

Sorry, but I do not understand yuor code at all. The radius R1 has to be equal to 0.6, and the center X1 not necessarily be the (0,0).

Also, your code return me an error: 

Error, invalid sequence
 

(for r in R do   do v:=Xrnd(r) until check(v,r); S(++NS) := [v, r]; od)

@acer 

Many thanks for your answer, but it is seems that PHCPack is not free: http://homepages.math.uic.edu/~jan/PHCpack/node11.html#SECTION000110000000000000000

@acer thanks for your comments.

@tomleslie thanks for your reply! Really, it is easier.

@dharr thanks for your comments!

@tomleslie 

Thank you very much. I feel that I do not defined well the Bernstein polynomials. Your definiton works!

@acer 

First at all, thanks for your reply. Yes, I have plotted correctly the Schubert function and the graph is as in the link https://www.sfu.ca/~ssurjano/shubert.html

My question is related to the plot the approximation by Bernstein polynomials (detailed in the cited paper in my post) of such function. That is, plot the function (x,y,p(x,y)), p(x,y) being the Berstein polynomial of f(x,y).

Maybe I have not defined this polynomial well, because the graph does not look like the Schubert function   plots.pdf

Again, thanks.

@acer Thanks!

@Kitonum your procedure returns me 

                         /   1\           /1   \
                RealRange|0, -|, RealRange|-, 1|
                         \   7/           \3   /
                  /         /   1\           /1   \\
           `union`|RealRange|0, -|, RealRange|-, 1||
                  \         \   7/           \3   //
 

but I really need to get [0,1/7], [1/3,1]. Can you help me with this, please?

Again, thanks

Thank you for your comments!! Are useful for me.

@acer  many thankls!! I feel that is what I wanted...

@Kitonum and @vv

Many thanks for your answers! If attache a "pioneer" paper on the issue on the Frechet distance between two polygonal lines, for if you are interested...This problem, in its general version, is very hard.

Also, in the following link, you can find some "hints", if you are interested, to code a program to compute the Frechet distance between two polygonal curves:

http://cgm.cs.mcgill.ca/~athens/cs507/Projects/2002/StephanePelletier/

https://github.com/spiros/discrete_frechet

I reiterate my gratitude.

@vv First at all, many thanks fopr the procedure.

It seems works correct and fastly!! :)

I reiterate my gratitude for your useful help.