jsMath
[3]  

The Birch and Swinnerton-Dyer Conjecture for 37A

This worksheet illustrates the conjecture of Birch and Swinnerton-Dyer for the elliptic curve

y2+y=x3x; 

affectionately referred to by mathematicians as 37a.

The Birch and Swinnerton-Dyer Conjecture for 37A

This worksheet illustrates the conjecture of Birch and Swinnerton-Dyer for the elliptic curve

y2+y=x3x;

affectionately referred to by mathematicians as 37a.

[24] 
An elliptic curve E  over Q  is a smooth projective curve determined by an equation

y2+a1xy+a3y=x3+a2x2+a4x+a6; 


with a1;a2;a3;a4;a62Q: 

EXAMPLE:

y2+y=x3x 
An elliptic curve E  over Q  is a smooth projective curve determined by an equation

y2+a1xy+a3y=x3+a2x2+a4x+a6;


with a1;a2;a3;a4;a62Q: 

EXAMPLE:

y2+y=x3x
E = EllipticCurve([0,0,1,-1,0])
G = plot(E, rgbcolor=(1,0,1), thickness=3)
show(G,dpi=160)
[0]  
E = EllipticCurve([0,0,1,-1,0])
P = E([0,0])
Q = P
for n in range(30):
    print '%-10s%-60s'%(n, Q)
    Q += P
[8]  
0         (0 : 0 : 1)                                                 
1         (1 : 0 : 1)                                                 
2         (-1 : -1 : 1)                                               
3         (2 : -3 : 1)                                                
4         (1/4 : -5/8 : 1)                                            
5         (6 : 14 : 1)                                                
6         (-5/9 : 8/27 : 1)                                           
7         (21/25 : -69/125 : 1)                                       
8         (-20/49 : -435/343 : 1)                                     
9         (161/16 : -2065/64 : 1)                                     
10        (116/529 : -3612/12167 : 1)                                 
11        (1357/841 : 28888/24389 : 1)                                
12        (-3741/3481 : -43355/205379 : 1)                            
13        (18526/16641 : -2616119/2146689 : 1)                        
14        (8385/98596 : -28076979/30959144 : 1)                       
15        (480106/4225 : 332513754/274625 : 1)                        
16        (-239785/2337841 : 331948240/3574558889 : 1)                
17        (12551561/13608721 : -8280062505/50202571769 : 1)           
18        (-59997896/67387681 : -641260644409/553185473329 : 1)       
19        (683916417/264517696 : -18784454671297/4302115807744 : 1)   
20        (1849037896/6941055969 : -318128427505160/578280195945297 : 1)
21        (51678803961/12925188721 : 10663732503571536/1469451780501769 : 1)
22        (-270896443865/384768368209 : 66316334575107447/238670664494938073 : 1)
23        (4881674119706/5677664356225 : -8938035295591025771/13528653463047586625 : 1)
24        (-16683000076735/61935294530404 : -588310630753491921045/487424450554237378792 : 1)
25        (997454379905326/49020596163841 : -31636113722016288336230/343216282443844010111 : 1)
26        (2786836257692691/16063784753682169 : -435912379274109872312968/2035972062206737347698803
: 1)
27        (213822353304561757/158432514799144041 :
41974401721854929811774227/63061816101171948456692661 : 1)
28        (-3148929681285740316/2846153597907293521 :
-2181616293371330311419201915/4801616835579099275862827431 : 1)
29        (79799551268268089761/62586636021357187216 :
-754388827236735824355996347601/495133617181351428873673516736 : 1)
0         (0 : 0 : 1)                                                 
1         (1 : 0 : 1)                                                 
2         (-1 : -1 : 1)                                               
3         (2 : -3 : 1)                                                
4         (1/4 : -5/8 : 1)                                            
5         (6 : 14 : 1)                                                
6         (-5/9 : 8/27 : 1)                                           
7         (21/25 : -69/125 : 1)                                       
8         (-20/49 : -435/343 : 1)                                     
9         (161/16 : -2065/64 : 1)                                     
10        (116/529 : -3612/12167 : 1)                                 
11        (1357/841 : 28888/24389 : 1)                                
12        (-3741/3481 : -43355/205379 : 1)                            
13        (18526/16641 : -2616119/2146689 : 1)                        
14        (8385/98596 : -28076979/30959144 : 1)                       
15        (480106/4225 : 332513754/274625 : 1)                        
16        (-239785/2337841 : 331948240/3574558889 : 1)                
17        (12551561/13608721 : -8280062505/50202571769 : 1)           
18        (-59997896/67387681 : -641260644409/553185473329 : 1)       
19        (683916417/264517696 : -18784454671297/4302115807744 : 1)   
20        (1849037896/6941055969 : -318128427505160/578280195945297 : 1)
21        (51678803961/12925188721 : 10663732503571536/1469451780501769 : 1)
22        (-270896443865/384768368209 : 66316334575107447/238670664494938073 : 1)
23        (4881674119706/5677664356225 : -8938035295591025771/13528653463047586625 : 1)
24        (-16683000076735/61935294530404 : -588310630753491921045/487424450554237378792 : 1)
25        (997454379905326/49020596163841 : -31636113722016288336230/343216282443844010111 : 1)
26        (2786836257692691/16063784753682169 : -435912379274109872312968/2035972062206737347698803 : 1)
27        (213822353304561757/158432514799144041 : 41974401721854929811774227/63061816101171948456692661 : 1)
28        (-3148929681285740316/2846153597907293521 : -2181616293371330311419201915/4801616835579099275862827431 : 1)
29        (79799551268268089761/62586636021357187216 : -754388827236735824355996347601/495133617181351428873673516736 : 1)
E = EllipticCurve([0,0,1,-1,0])
G = plot(E, thickness=.6, rgbcolor=(1,0,1))
Q = P
n = 100
for i in range(n):
    Q = Q + P
    if abs(Q[0]) < 3 and abs(Q[1]) < 5:
        G += point(Q,rgbcolor=(1,0,0),pointsize=10+float(i)*100/n)
show(G,dpi=150)
[11] 
t = Tachyon(xres=1000, yres=800, camera_center=(2,7,4), look_at=(2,0,0), raydepth=4)
t.light((10,3,2), 1, (1,1,1))
t.light((10,-3,2), 1, (1,1,1))
t.texture('black', color=(0,0,0))
t.texture('red', color=(1,0,0))
t.texture('grey', color=(.9,.9,.9))
t.plane((0,0,0),(0,0,1),'grey')
t.cylinder((0,0,0),(1,0,0),.01,'black')
t.cylinder((0,0,0),(0,1,0),.01,'black')

E = EllipticCurve('37a')
P = E([0,0])
Q = P
n = 100
for i in range(n):  
    Q = Q + P
    c = i/n + .1
    t.texture('r%s'%i,color=(float(i/n),0,0))
    t.sphere((Q[0], -Q[1], .01), .04, 'r%s'%i)
          
t.save()
[6]  
[7]  

A Sharp Contrast:

  1. The elliptic curve y2+y=x3x  has infinitely many rational points.
  2. The elliptic curve y2+y=x3x2  has only finitely many rational points!

Question 1: Is there an a priori way to tell which type of elliptic curve we are dealing with?
Question 2: How often does each possibility occur? (Conjecture: 50% each -- See Bektemirov, Mazur, Stein, Watkins)

A Sharp Contrast:

  1. The elliptic curve y2+y=x3x has infinitely many rational points.
  2. The elliptic curve y2+y=x3x2 has only finitely many rational points!

Question 1: Is there an a priori way to tell which type of elliptic curve we are dealing with?
Question 2: How often does each possibility occur? (Conjecture: 50% each -- See Bektemirov, Mazur, Stein, Watkins)

[13] 
The L-function of an elliptic curve is a function on the complex numbers defined by counting points modulo primes:

L(E;s)=Yp11apps+p12s:

Formally: L(E;1)=Ypp#E(Fp):
The L-function of an elliptic curve is a function on the complex numbers defined by counting points modulo primes:

L(E;s)=Yp11apps+p12s:

Formally: L(E;1)=Ypp#E(Fp):
# Some Pictures of Counting Points
E = EllipticCurve([0,0,1,-1,0])
G = [plot(E.change_ring(GF(p)), pointsize=30, rgbcolor=(1,0,0))\
        for p in primes(42) if p!=37]
show(graphics_array(G,4,3),fontsize=4)
[14] 
# Tally up the number of points (including point at infinity)

E = EllipticCurve([0,0,1,-1,0])
print '.'*40
print '%10s%-2s%10s%13s'%('','p','N_p', 'p+1-N_p')
for p in primes(1000):
    print '%10s%-10s%-10s%-10s'%('',p,E.Np(p),E.ap(p))
[16] 
........................................
          p        N_p      p+1-N_p
          2         5         -2        
          3         7         -3        
          5         8         -2        
          7         9         -1        
          11        17        -5        
          13        16        -2        
          17        18        0         
          19        20        0         
          23        22        2         
          29        24        6         
          31        36        -4        
          37        39        -1        
          41        51        -9        
          43        42        2         
          47        57        -9        
          53        53        1         
          59        52        8         
          61        70        -8        
          67        60        8         
          71        63        9         
          73        75        -1        
          79        76        4         
          83        99        -15       
          89        86        4         
          97        94        4         
          101       99        3         
          103       86        18        
          107       120       -12       
          109       126       -16       
          113       132       -18       
          127       127       1         
          131       144       -12       
          137       144       -6        
          139       136       4         
          149       155       -5        
          151       136       16        
          157       135       23        
          163       182       -18       
          167       180       -12       
          173       165       9         
          179       162       18        
          181       177       5         
          191       196       -4        
          193       220       -26       
          197       195       3         
          199       198       2         
          211       225       -13       
          223       241       -17       
          227       244       -16       
          229       223       7         
          233       228       6         
          239       246       -6        
          241       228       14        
          251       254       -2        
          257       258       0         
          263       245       19        
          269       276       -6        
          271       303       -31       
          277       266       12        
          281       270       12        
          283       280       4         
          293       296       -2        
          307       325       -17       
          311       312       0         
          313       292       22        
          317       296       22        
          331       334       -2        
          337       363       -25       
          347       358       -10       
          349       344       6         
          353       346       8         
          359       375       -15       
          367       360       8         
          373       393       -19       
          379       365       15        
          383       364       20        
          389       386       4         
          397       403       -5        
          401       384       18        
          409       390       20        
          419       413       7         
          421       446       -24       
          431       462       -30       
          433       425       9         
          439       412       28        
          443       443       1         
          449       414       36        
          457       440       18        
          461       432       30        
          463       486       -22       
          467       470       -2        
          479       466       14        
          487       512       -24       
          491       520       -28       
          499       488       12        
          503       488       16        
          509       541       -31       
          521       555       -33       
          523       546       -22       
          541       522       20        
          547       540       8         
          557       576       -18       
          563       594       -30       
          569       594       -24       
          571       565       7         
          577       578       0         
          587       620       -32       
          593       599       -5        
          599       599       1         
          601       624       -22       
          607       640       -32       
          613       599       15        
          617       601       17        
          619       621       -1        
          631       660       -28       
          641       643       -1        
          643       630       14        
          647       656       -8        
          653       678       -24       
          659       675       -15       
          661       690       -28       
          673       647       27        
          677       689       -11       
          683       666       18        
          691       712       -20       
          701       714       -12       
          709       670       40        
          719       681       39        
          727       712       16        
          733       727       7         
          739       749       -9        
          743       723       21        
          751       727       25        
          757       808       -50       
          761       797       -35       
          769       744       26        
          773       783       -9        
          787       793       -5        
          797       746       52        
          809       808       2         
          811       765       47        
          821       869       -47       
          823       840       -16       
          827       806       22        
          829       834       -4        
          839       796       44        
          853       828       26        
          857       906       -48       
          859       880       -20       
          863       888       -24       
          877       828       50        
          881       896       -14       
          883       836       48        
          887       863       25        
          907       856       52        
          911       886       26        
          919       978       -58       
          929       912       18        
          937       901       37        
          941       952       -10       
          947       936       12        
          953       893       61        
          967       982       -14       
          971       980       -8        
          977       950       28        
          983       975       9         
          991       1010      -18       
          997       1040      -42
........................................
          p        N_p      p+1-N_p
          2         5         -2        
          3         7         -3        
          5         8         -2        
          7         9         -1        
          11        17        -5        
          13        16        -2        
          17        18        0         
          19        20        0         
          23        22        2         
          29        24        6         
          31        36        -4        
          37        39        -1        
          41        51        -9        
          43        42        2         
          47        57        -9        
          53        53        1         
          59        52        8         
          61        70        -8        
          67        60        8         
          71        63        9         
          73        75        -1        
          79        76        4         
          83        99        -15       
          89        86        4         
          97        94        4         
          101       99        3         
          103       86        18        
          107       120       -12       
          109       126       -16       
          113       132       -18       
          127       127       1         
          131       144       -12       
          137       144       -6        
          139       136       4         
          149       155       -5        
          151       136       16        
          157       135       23        
          163       182       -18       
          167       180       -12       
          173       165       9         
          179       162       18        
          181       177       5         
          191       196       -4        
          193       220       -26       
          197       195       3         
          199       198       2         
          211       225       -13       
          223       241       -17       
          227       244       -16       
          229       223       7         
          233       228       6         
          239       246       -6        
          241       228       14        
          251       254       -2        
          257       258       0         
          263       245       19        
          269       276       -6        
          271       303       -31       
          277       266       12        
          281       270       12        
          283       280       4         
          293       296       -2        
          307       325       -17       
          311       312       0         
          313       292       22        
          317       296       22        
          331       334       -2        
          337       363       -25       
          347       358       -10       
          349       344       6         
          353       346       8         
          359       375       -15       
          367       360       8         
          373       393       -19       
          379       365       15        
          383       364       20        
          389       386       4         
          397       403       -5        
          401       384       18        
          409       390       20        
          419       413       7         
          421       446       -24       
          431       462       -30       
          433       425       9         
          439       412       28        
          443       443       1         
          449       414       36        
          457       440       18        
          461       432       30        
          463       486       -22       
          467       470       -2        
          479       466       14        
          487       512       -24       
          491       520       -28       
          499       488       12        
          503       488       16        
          509       541       -31       
          521       555       -33       
          523       546       -22       
          541       522       20        
          547       540       8         
          557       576       -18       
          563       594       -30       
          569       594       -24       
          571       565       7         
          577       578       0         
          587       620       -32       
          593       599       -5        
          599       599       1         
          601       624       -22       
          607       640       -32       
          613       599       15        
          617       601       17        
          619       621       -1        
          631       660       -28       
          641       643       -1        
          643       630       14        
          647       656       -8        
          653       678       -24       
          659       675       -15       
          661       690       -28       
          673       647       27        
          677       689       -11       
          683       666       18        
          691       712       -20       
          701       714       -12       
          709       670       40        
          719       681       39        
          727       712       16        
          733       727       7         
          739       749       -9        
          743       723       21        
          751       727       25        
          757       808       -50       
          761       797       -35       
          769       744       26        
          773       783       -9        
          787       793       -5        
          797       746       52        
          809       808       2         
          811       765       47        
          821       869       -47       
          823       840       -16       
          827       806       22        
          829       834       -4        
          839       796       44        
          853       828       26        
          857       906       -48       
          859       880       -20       
          863       888       -24       
          877       828       50        
          881       896       -14       
          883       836       48        
          887       863       25        
          907       856       52        
          911       886       26        
          919       978       -58       
          929       912       18        
          937       901       37        
          941       952       -10       
          947       936       12        
          953       893       61        
          967       982       -14       
          971       980       -8        
          977       950       28        
          983       975       9         
          991       1010      -18       
          997       1040      -42
[23] 

ASIDE -- big recent theorem of Taylor, Harris,
Clozel, Shepherd-Barron

THE SATO-TATE CONJECTURE is a theorem
(in a wide range of cases).

ASIDE -- big recent theorem of Taylor, Harris,
Clozel, Shepherd-Barron

THE SATO-TATE CONJECTURE is a theorem
(in a wide range of cases).
[17] 
Recall that the L -series of E  is

L(E;s)=Yp11apps+p12s:


where

ap=p+1#E(Z=pZ) 
Recall that the L -series of E  is

L(E;s)=Yp11apps+p12s:


where

ap=p+1#E(Z=pZ) 
# Compute the L-series of E
E = EllipticCurve([0,0,1,-1,0])
L = E.Lseries_dokchitser(10)     # Tim Dokchitser
plot(L, -2,3, rgbcolor=(0,0,1), plot_points=90, \
         plot_division=0, thickness=2).show()
[18] 
t = Tachyon(xres=800, yres=600, camera_center=(1.2,.4,.4), look_at=(1,0,0), raydepth=2)
t.light((10,3,2), 1, (1,1,1))
t.light((10,-3,2), 1, (1,1,1))
t.texture('black', color=(0,0,0))
t.texture('red', color=(1,0,0))
t.texture('white', color=(1,1,1))
t.plane((0,0,-10),(0,0,1),'white')
t.cylinder((0,0,0),(1,0,0),.001,'black')
t.cylinder((0,0,0),(0,1,0),.001,'black')

n=1000
for i in range(n): 
    x = random()/2+.8; y = random()/2 - .25
    try:
        z = L(x+I*y)
        m = abs(z)
        r = arg(z)+pi
    except:
        continue

    t.texture('r%s'%i,color=(r/7,r,0))
    t.sphere((x,-y,m), .009, 'r%s'%i)
          
t.show()
[19] 
t = Tachyon(xres=800, yres=600, camera_center=(1.2,.4,.4), look_at=(1,0,0), raydepth=2)
t.light((10,3,2), 1, (1,1,1))
t.light((10,-3,2), 1, (1,1,1))
t.texture('black', color=(0,0,0))
t.texture('red', color=(1,0,0))
t.texture('white', color=(1,1,1))
t.plane((0,0,-10),(0,0,1),'white')
t.cylinder((0,0,0),(1,0,0),.001,'black')
t.cylinder((0,0,0),(0,1,0),.001,'black')

n=10000
for i in range(n): 
    x = random()/2+.8; y = random()/2 - .25
    try:
        z = L(x+I*y)
        m = abs(z)
        r = arg(z)+pi
    except:
        continue

    t.texture('r%s'%i,color=(r/7,r,0))
    t.sphere((x,-y,m), .005, 'r%s'%i)
          
t.show()
[26] 
print """
<html><font color=black>
<h1>Birch's Parallel Lines?</h1>
</html>
"""

E = [EllipticCurve('11a'),  EllipticCurve('37a'),
     EllipticCurve('389a'), EllipticCurve('5077a')]

def f(E, B=1000, **args):
    v = []; pr = 1
    for p in prime_range(2,B):
        pr *=  float(p/E.Np(p))
        if p >= 5:
           v.append((p, pr))
    return line(v, **args) + point(v,**args)

G = sum([f(E[i],rgbcolor=(i/4.0,0,1-i/4.0)) for i in range(4)])
show(G,ymin=0,ymax=.25,dpi=200)
[27] 

Birch's Parallel Lines?


Birch's Parallel Lines?

[21] 
Conjecture (Birch and Swinnerton-Dyer):
     ords=1L(E;s)=rank E 

  1. This is a theorem when the order of vanishing is 0 or 1.

  2. It is a million dollar Clay Problem.

  3. It is an open problem to prove that the order of vanishing can ever be 4 or larger.

  4. There is also a beautiful conjecture (that is very useful computationally!) about the first nonzero coefficient of the Taylor expansion of L(E;s)  about s=1 .
(back to slides)
Conjecture (Birch and Swinnerton-Dyer):
     ords=1L(E;s)=rank E 

  1. This is a theorem when the order of vanishing is 0 or 1.

  2. It is a million dollar Clay Problem.

  3. It is an open problem to prove that the order of vanishing can ever be 4 or larger.

  4. There is also a beautiful conjecture (that is very useful computationally!) about the first nonzero coefficient of the Taylor expansion of L(E;s)  about s=1 .
(back to slides)
[22]