cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-3 of 3 results.

A121732 Dimensions of the irreducible representations of the simple Lie algebra of type E8 over the complex numbers, listed in increasing order.

Original entry on oeis.org

1, 248, 3875, 27000, 30380, 147250, 779247, 1763125, 2450240, 4096000, 4881384, 6696000, 26411008, 70680000, 76271625, 79143000, 146325270, 203205000, 281545875, 301694976, 344452500, 820260000, 1094951000, 2172667860
Offset: 1

Views

Author

Skip Garibaldi (skip(AT)mathcs.emory.edu), Aug 18 2006

Keywords

Comments

We include "1" for the 1-dimensional trivial representation and we list each dimension once, ignoring the possibility that inequivalent representations may have the same dimension.
Inequivalent representations can have the same dimension. For example, the highest weights 10100000 and 10000011 (with fundamental weights numbered as in Bourbaki) both correspond to irreducible representations of dimension 8634368000.

Examples

			The highest weight 00000000 corresponds to the 1-dimensional module on which E8 acts trivially. The smallest faithful representation of E8 is the adjoint representation of dimension 248 (the second term in the sequence), with highest weight 00000001. The smallest non-fundamental representation has dimension 27000 (the fourth term), corresponding to the highest weight 00000002.
		

References

  • J. E. Humphreys, Introduction to Lie algebras and representation theory, Springer, 1997.

Crossrefs

Programs

  • GAP
    # see program given in link.

Formula

Given a vector of 8 nonnegative integers, the Weyl dimension formula tells you the dimension of the corresponding irreducible representation. The list of such dimensions is then sorted numerically.

A121741 Dimensions of the irreducible representations of the simple Lie algebra of type A2 (equivalently, the group SL3) over the complex numbers, listed in increasing order.

Original entry on oeis.org

1, 3, 6, 8, 10, 15, 21, 24, 27, 28, 35, 36, 42, 45, 48, 55, 60, 63, 64, 66, 78, 80, 81, 90, 91, 99, 105, 120, 125, 132, 136, 143, 153, 154, 162, 165, 168, 171, 190, 192, 195, 210, 216, 224, 231, 234, 253, 255, 260, 270, 273, 276, 280, 288, 300
Offset: 1

Views

Author

Skip Garibaldi (skip(AT)member.ams.org), Aug 19 2006, Aug 23 2006

Keywords

Comments

We include "1" for the 1-dimensional trivial representation and we list each dimension once, ignoring the fact that inequivalent representations may have the same dimension.
Numbers of the form (x * (x - y) * (x - z) + y * (y - x) * (y - z) + z * (z - x) * (z - y)) / 18 with x + y + z = 0 and x * y * z > 0. - Michael Somos, Jun 26 2013
Positive numbers of the form (r-s)*r*(r+s) where r and s are integers, i.e., the product of three integers in arithmetic progression. In the expression above, set x = r-s, y = r+s, and z = -x-y. - Elliott Line, Dec 22 2020

References

  • N. Bourbaki, Lie groups and Lie algebras, Chapters 4-6, Springer, 2002.
  • J. E. Humphreys, Introduction to Lie algebras and representation theory, Springer, 1997.

Crossrefs

Programs

  • GAP
    # see program at sequence A121732
    
  • Python
    from itertools import count, islice
    from sympy import divisors, integer_nthroot
    def A121741_gen(startvalue=1): # generator of terms >= startvalue
        for m in count(max(startvalue,1)):
            for k in divisors(m<<1,generator=True):
                p, q = integer_nthroot(k**4+(k*m<<3),2)
                if q and not (p-k**2)%(k<<1):
                    yield m
                    break
    A121741_list = list(islice(A121741_gen(),20)) # Chai Wah Wu, Jul 03 2023

A263005 Dimensions of the simple Lie algebras over complex numbers (with repetitions), sorted nondecreasingly.

Original entry on oeis.org

3, 8, 10, 14, 15, 21, 21, 24, 28, 35, 36, 36, 45, 48, 55, 55, 57, 63, 66, 78, 78, 78, 80, 91, 99, 105, 105, 120, 120, 133, 136, 136, 143, 153, 168, 171, 171, 190, 195, 210, 210, 224, 231, 248, 253, 253, 255, 276, 288, 300, 300
Offset: 1

Views

Author

Wolfdieter Lang, Oct 23 2015

Keywords

Comments

This sequence gives the dimensions of the (compact) simple Lie algebras A_l, l >= 1, B_l, l >= 2, C_l >= 3, D_l, l >= 4, E_6, E_7, E_8, F_4 and G_2 which are l*(l+2), l*(2*l + 1), l*(2*l + 1), l*(2*l - 1), 78, 133, 248, 52 and 14, respectively. These are also the dimensions of the adjoint representations of these Lie algebras. For the l-ranges see the Humphreys reference, p. 58, and for the dimensions, e.g., the Samelson link, Theorem A, p. 74.
The dimension duplications occur for the B_l and C_l series for l >= 3.

References

  • E. Cartan, Sur la structure des groupes de transformation finis et continus. Thèse Paris 1894. Oeuvres Complètes, I,1, pp. 137-287, Paris 1952.
  • J. E. Humphreys, Introduction to Lie algebras and representation theory, Springer, 1972.

Crossrefs

Showing 1-3 of 3 results.