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Alec Mihailovs

Dr. Aleksandrs Mihailovs

4495 Reputation

21 Badges

20 years, 339 days
Mihailovs, Inc.
Owner, President, and CEO
Tyngsboro, Massachusetts, United States

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Contact Dr. Aleksandrs Mihailovs

I received my Ph.D. from the University of Pennsylvania in 1998 and I have been teaching since then at SUNY Oneonta for 1 year, at Shepherd University for 5 years, at Tennessee Tech for 2 years, at Lane College for 1 year, and this year I taught at the University of Massachusetts Lowell. My research interests include Representation Theory and Combinatorics.

MaplePrimes Activity


These are replies submitted by Alec Mihailovs

indices...

Alec Mihailovs 4495
July 30 2009
0 0 
intp:=indices@Array;

also seem to be working OK.

I wonder if there is an easy way to profile the speed and memory usage.

Alec

indices...

Alec Mihailovs 4495
July 30 2009 
intp:=indices@Array;

also seem to be working OK.

I wonder if there is an easy way to profile the speed and memory usage.

Alec

A problem...

Alec Mihailovs 4495
July 28 2009

A slight problem with that may be that only very simple things are properly converted, like 2+2. Everything else still needs manual work - and many things working in Mathematica don't work in Maple.

Alec

Mathematica...

Alec Mihailovs 4495
July 28 2009

For the record, here is Mathematica's output

In[1]:= Reduce[5 x^2 + 11 x y - 5 y^2 == 11, Integers]

Out[1]= (C[1] \[Element] Integers && C[1] >= 0 && 
   x == 1/442 (1547 (1665 - 112 Sqrt[221])^C[1] - 
       103 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] + 
       1547 (1665 + 112 Sqrt[221])^C[1] + 
       103 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) && 
   y == (1/2210)(-(11/
        2) (-1547 (1665 - 112 Sqrt[221])^C[1] + 
         103 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] - 
         1547 (1665 + 112 Sqrt[221])^C[1] - 
         103 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) - 
      221/2 (-103 (1665 - 112 Sqrt[221])^C[1] + 
         7 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] - 
         103 (1665 + 112 Sqrt[221])^C[1] - 
         7 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]))) || (C[
     1] \[Element] Integers && C[1] >= 0 && 
   x == 1/442 (-1547 (1665 - 112 Sqrt[221])^C[1] - 
       103 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] - 
       1547 (1665 + 112 Sqrt[221])^C[1] + 
       103 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) && 
   y == (1/2210)(-(11/
        2) (1547 (1665 - 112 Sqrt[221])^C[1] + 
         103 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] + 
         1547 (1665 + 112 Sqrt[221])^C[1] - 
         103 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) - 
      221/2 (103 (1665 - 112 Sqrt[221])^C[1] + 
         7 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] + 
         103 (1665 + 112 Sqrt[221])^C[1] - 
         7 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]))) || (C[
     1] \[Element] Integers && C[1] >= 0 && 
   x == 1/221 (884 (1665 - 112 Sqrt[221])^C[1] - 
       59 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] + 
       884 (1665 + 112 Sqrt[221])^C[1] + 
       59 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) && 
   y == (1/2210)(-11 (-884 (1665 - 112 Sqrt[221])^C[1] + 
         59 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] - 
         884 (1665 + 112 Sqrt[221])^C[1] - 
         59 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) - 
      221 (59 (1665 - 112 Sqrt[221])^C[1] - 
         4 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] + 
         59 (1665 + 112 Sqrt[221])^C[1] + 
         4 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]))) || (C[
     1] \[Element] Integers && C[1] >= 0 && 
   x == 1/221 (-884 (1665 - 112 Sqrt[221])^C[1] - 
       59 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] - 
       884 (1665 + 112 Sqrt[221])^C[1] + 
       59 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) && 
   y == (1/2210)(-11 (884 (1665 - 112 Sqrt[221])^C[1] + 
         59 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] + 
         884 (1665 + 112 Sqrt[221])^C[1] - 
         59 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) - 
      221 (-59 (1665 - 112 Sqrt[221])^C[1] - 
         4 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] - 
         59 (1665 + 112 Sqrt[221])^C[1] + 
         4 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]))) || (C[
     1] \[Element] Integers && C[1] >= 0 && 
   x == 1/442 (221 (1665 - 112 Sqrt[221])^C[1] - 
       Sqrt[221] (1665 - 112 Sqrt[221])^C[1] + 
       221 (1665 + 112 Sqrt[221])^C[1] + 
       Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) && 
   y == (1/2210)(-(11/
        2) (-221 (1665 - 112 Sqrt[221])^C[1] + 
         Sqrt[221] (1665 - 112 Sqrt[221])^C[1] - 
         221 (1665 + 112 Sqrt[221])^C[1] - 
         Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) - 
      221/2 ((1665 - 112 Sqrt[221])^C[1] - 
         Sqrt[221] (1665 - 112 Sqrt[221])^
          C[1] + (1665 + 112 Sqrt[221])^C[1] + 
         Sqrt[221] (1665 + 112 Sqrt[221])^C[1]))) || (C[1] \[Element] 
    Integers && C[1] >= 0 && 
   x == 1/442 (-221 (1665 - 112 Sqrt[221])^C[1] - 
       Sqrt[221] (1665 - 112 Sqrt[221])^C[1] - 
       221 (1665 + 112 Sqrt[221])^C[1] + 
       Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) && 
   y == (1/2210)(-(11/
        2) (221 (1665 - 112 Sqrt[221])^C[1] + 
         Sqrt[221] (1665 - 112 Sqrt[221])^C[1] + 
         221 (1665 + 112 Sqrt[221])^C[1] - 
         Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) - 
      221/2 (-(1665 - 112 Sqrt[221])^C[1] - 
         Sqrt[221] (1665 - 112 Sqrt[221])^
          C[1] - (1665 + 112 Sqrt[221])^C[1] + 
         Sqrt[221] (1665 + 112 Sqrt[221])^C[1]))) || (C[1] \[Element] 
    Integers && C[1] >= 0 && 
   x == 1/442 (221 (1665 - 112 Sqrt[221])^C[1] + 
       Sqrt[221] (1665 - 112 Sqrt[221])^C[1] + 
       221 (1665 + 112 Sqrt[221])^C[1] - 
       Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) && 
   y == (1/2210)(-(221/
        2) ((1665 - 112 Sqrt[221])^C[1] + 
         Sqrt[221] (1665 - 112 Sqrt[221])^
          C[1] + (1665 + 112 Sqrt[221])^C[1] - 
         Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) - 
      11/2 (-221 (1665 - 112 Sqrt[221])^C[1] - 
         Sqrt[221] (1665 - 112 Sqrt[221])^C[1] - 
         221 (1665 + 112 Sqrt[221])^C[1] + 
         Sqrt[221] (1665 + 112 Sqrt[221])^C[1]))) || (C[1] \[Element] 
    Integers && C[1] >= 0 && 
   x == 1/442 (-221 (1665 - 112 Sqrt[221])^C[1] + 
       Sqrt[221] (1665 - 112 Sqrt[221])^C[1] - 
       221 (1665 + 112 Sqrt[221])^C[1] - 
       Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) && 
   y == (1/2210)(-(221/
        2) (-(1665 - 112 Sqrt[221])^C[1] + 
         Sqrt[221] (1665 - 112 Sqrt[221])^
          C[1] - (1665 + 112 Sqrt[221])^C[1] - 
         Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) - 
      11/2 (221 (1665 - 112 Sqrt[221])^C[1] - 
         Sqrt[221] (1665 - 112 Sqrt[221])^C[1] + 
         221 (1665 + 112 Sqrt[221])^C[1] + 
         Sqrt[221] (1665 + 112 Sqrt[221])^C[1]))) || (C[1] \[Element] 
    Integers && C[1] >= 0 && 
   x == 1/221 (884 (1665 - 112 Sqrt[221])^C[1] + 
       59 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] + 
       884 (1665 + 112 Sqrt[221])^C[1] - 
       59 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) && 
   y == (1/2210)(-221 (59 (1665 - 112 Sqrt[221])^C[1] + 
         4 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] + 
         59 (1665 + 112 Sqrt[221])^C[1] - 
         4 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) - 
      11 (-884 (1665 - 112 Sqrt[221])^C[1] - 
         59 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] - 
         884 (1665 + 112 Sqrt[221])^C[1] + 
         59 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]))) || (C[
     1] \[Element] Integers && C[1] >= 0 && 
   x == 1/221 (-884 (1665 - 112 Sqrt[221])^C[1] + 
       59 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] - 
       884 (1665 + 112 Sqrt[221])^C[1] - 
       59 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) && 
   y == (1/2210)(-221 (-59 (1665 - 112 Sqrt[221])^C[1] + 
         4 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] - 
         59 (1665 + 112 Sqrt[221])^C[1] - 
         4 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) - 
      11 (884 (1665 - 112 Sqrt[221])^C[1] - 
         59 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] + 
         884 (1665 + 112 Sqrt[221])^C[1] + 
         59 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]))) || (C[
     1] \[Element] Integers && C[1] >= 0 && 
   x == 1/442 (1547 (1665 - 112 Sqrt[221])^C[1] + 
       103 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] + 
       1547 (1665 + 112 Sqrt[221])^C[1] - 
       103 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) && 
   y == (1/2210)(-(221/
        2) (-103 (1665 - 112 Sqrt[221])^C[1] - 
         7 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] - 
         103 (1665 + 112 Sqrt[221])^C[1] + 
         7 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) - 
      11/2 (-1547 (1665 - 112 Sqrt[221])^C[1] - 
         103 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] - 
         1547 (1665 + 112 Sqrt[221])^C[1] + 
         103 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]))) || (C[
     1] \[Element] Integers && C[1] >= 0 && 
   x == 1/442 (-1547 (1665 - 112 Sqrt[221])^C[1] + 
       103 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] - 
       1547 (1665 + 112 Sqrt[221])^C[1] - 
       103 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) && 
   y == (1/2210)(-(221/
        2) (103 (1665 - 112 Sqrt[221])^C[1] - 
         7 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] + 
         103 (1665 + 112 Sqrt[221])^C[1] + 
         7 Sqrt[221] (1665 + 112 Sqrt[221])^C[1]) - 
      11/2 (1547 (1665 - 112 Sqrt[221])^C[1] - 
         103 Sqrt[221] (1665 - 112 Sqrt[221])^C[1] + 
         1547 (1665 + 112 Sqrt[221])^C[1] + 
         103 Sqrt[221] (1665 + 112 Sqrt[221])^C[1])))

In[2]:= FullSimplify[% /. Table[{C[1] -> i}, {i, 0, 5}]]

Out[2]= {(x == -8 && y == 3) || (x == -7 && y == -18) || (x == -1 && 
    y == -1) || (x == 1 && y == 1) || (x == 7 && y == 18) || (x == 8 &&
     y == -3), (x == 23191 && y == 59986) || (x == -119 && 
    y == 46) || (x == 26536 && y == -10259) || (x == -104 && 
    y == -269) || (x == 1777 && y == -687) || (x == -1553 && 
    y == -4017) || (x == 1553 && y == 4017) || (x == -1777 && 
    y == 687) || (x == 104 && y == 269) || (x == -26536 && 
    y == 10259) || (x == 119 && y == -46) || (x == -23191 && 
    y == -59986), (x == 77226023 && y == 199753362) || (x == -396263 &&
     y == 153198) || (x == 88364872 && 
    y == -34162467) || (x == -346312 && 
    y == -895773) || (x == 5917409 && 
    y == -2287711) || (x == -5171489 && 
    y == -13376609) || (x == 5171489 && 
    y == 13376609) || (x == -5917409 && 
    y == 2287711) || (x == 346312 && y == 895773) || (x == -88364872 &&
     y == 34162467) || (x == 396263 && 
    y == -153198) || (x == -77226023 && 
    y == -199753362), (x == 257162633399 && 
    y == 665178635474) || (x == -1319555671 && 
    y == 510149294) || (x == 294254997224 && 
    y == -113761004851) || (x == -1153218856 && 
    y == -2982923821) || (x == 19704970193 && 
    y == -7618076943) || (x == -17221056817 && 
    y == -44544103953) || (x == 17221056817 && 
    y == 44544103953) || (x == -19704970193 && 
    y == 7618076943) || (x == 1153218856 && 
    y == 2982923821) || (x == -294254997224 && 
    y == 113761004851) || (x == 1319555671 && 
    y == -510149294) || (x == -257162633399 && 
    y == -665178635474), (x == 856351491992647 && 
    y == 2215044656375058) || (x == -4394119988167 && 
    y == 1698796995822) || (x == 979869052391048 && 
    y == -378824111991363) || (x == -3840218444168 && 
    y == -9933135428157) || (x == 65617544825281 && 
    y == -25368193932479) || (x == -57346114029121 && 
    y == -148331852786881) || (x == 57346114029121 && 
    y == 148331852786881) || (x == -65617544825281 && 
    y == 25368193932479) || (x == 3840218444168 && 
    y == 9933135428157) || (x == -979869052391048 && 
    y == 378824111991363) || (x == 4394119988167 && 
    y == -1698796995822) || (x == -856351491992647 && 
    y == -2215044656375058), (x == 2851650211172881111 && 
    y == 7376098040550307666) || (x == -14632418241040439 && 
    y == 5656993485937966) || (x == 3262963650207192616 && 
    y == -1261484179170233939) || (x == -12787926265860584 && 
    y == -33077337992838989) || (x == 218506404563215537 && 
    y == -84476078177078127) || (x == -190962542495916113 && 
    y == -493945025236209777) || (x == 190962542495916113 && 
    y == 493945025236209777) || (x == -218506404563215537 && 
    y == 84476078177078127) || (x == 12787926265860584 && 
    y == 33077337992838989) || (x == -3262963650207192616 && 
    y == 1261484179170233939) || (x == 14632418241040439 && 
    y == -5656993485937966) || (x == -2851650211172881111 && 
    y == -7376098040550307666)}

Alec

I don't use Maple...

Alec Mihailovs 4495
July 16 2009
0 0

That may be a useful trick. However, I don't use Maple.

I started using it last year (in May, I think) exclusively for this site posts, then I got a Maple mentor award (a mug), and a complimentary copy of Maple 12, so I felt obligated to continue posting here (and using Maple for that.)

This year, I get neither a mug nor a complimentary copy of Maple 13, so I don't feel obligated to post here or using Maple anymore. Plus I switched to Windows 7 and I don't have an additional license even to check whether Maple is working there or not.

Alec

I don't use Maple...

Alec Mihailovs 4495
July 16 2009

That may be a useful trick. However, I don't use Maple.

I started using it last year (in May, I think) exclusively for this site posts, then I got a Maple mentor award (a mug), and a complimentary copy of Maple 12, so I felt obligated to continue posting here (and using Maple for that.)

This year, I get neither a mug nor a complimentary copy of Maple 13, so I don't feel obligated to post here or using Maple anymore. Plus I switched to Windows 7 and I don't have an additional license even to check whether Maple is working there or not.

Alec

What happens?...

Alec Mihailovs 4495
May 28 2009

No monthly awards, no quaterly awards... Did Maplesoft run out of pens and mugs? Are Maple 13 sales really that bad? Will be at least a half-year award (we know that the yearly award is not planned)?

Alec

Thank you...

Alec Mihailovs 4495
May 28 2009

Thank you,

I, probably, misconfigured my email there, because I didn't get anything in email (while getting a lot of spam from other Linkedin networks that I am a member  of.) 

Alec

When?...

Alec Mihailovs 4495
May 28 2009

I am still wondering when this reaching to the Maple community on Linkedin is scheduled?

I've subscribed to it from the very beginning and as far as I can tell, nothing was even posted there thus far.

Is it going to happen this year, or it is a lifetime effort?

Alec

Then...

Alec Mihailovs 4495
May 28 2009

But then I would be well ahead of anybody which doesn't seem fair.

Plus, I doubt that this site keeps a record of our scores a year ago. Actually, I would be very surprised if it does.

It could be recovered though, probably - it is not that hard to write a script, bla bla bla (perhaps, not for the current site administrators though - but it is a different topic.)

Another problem with this site is that my posts get deleted from time to time. About a month ago my score was 2064, then I didn't post for a month and my score dropped to 2053. One of my deleted posts I was able to recover - it was a reply to a guy double posting his question - I answered to it in one thread, which was deleted later, together with my response, and instead Tim Vrablic posted a short version of my response in another thread, getting a point for himself and decreasing the number of my points.

Alec

Finally...

Alec Mihailovs 4495
May 28 2009

Nothing seems to be done here, but I implemented that manually (currently, only 3 people are on my Ignore list).

Alec

Time for revision...

Alec Mihailovs 4495
May 27 2009

I think these numbers, 400, 200, 80, and 10 should be revised by this time. One way to do that is to multiply them by some number between 3 and 5. My choice would be 5, but 4 might be good as well.

Also, as I've mentioned already, some colors could be changed because it's hard to tell the difference between 200 points and 10 points icons. Perhaps, using multiple icons instead would be better - like 5 Maple leaves, or 4 Maple leaves etc. - both for the accessibility and black and white printing.

Alec Mihailovs, PhD
Mihailovs, Inc. President and CEO

A;...

Alec Mihailovs 4495
May 26 2009
0 0

Just type

A;

Alec

A;...

Alec Mihailovs 4495
May 26 2009

Just type

A;

Alec

You mean 10?...

Alec Mihailovs 4495
May 26 2009
0 0

As far as I recall, the default is 10 in GUI and 25 in the command line.

Alec

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