06-1350/Class Notes for Thursday November 16

From Drorbn

Today's Agenda

Formulas are a Chore (Bore?)

  • Sweeping clean a tree and {\mathcal A}(\Gamma)\equiv{\mathcal A}(\uparrow_{b_1(\Gamma)}).
  • In the coordinates above, write the TRΦB relations in various algebraic notations.
    • R4: (1230)^\star B\cdot(1213)^\star B\cdot(1023)^\star\Phi=(1123)^\star\Phi\cdot(1233)^\star B or (B1aB2aΦ1a;B1bB2b;B1cB2aΦ1b;B2cΦ1c) = (Φ2aB3a2aB3b2bB3c2cB3c).
    • R3: (1230)^\star B\cdot(1213)^\star B\cdot(1023)^\star B = (1123)^\star B\cdot(1203)^\star B\cdot(1231)^\star B or (B1aB2aB3a;B1bB2b;B1cB2aB3b;B2cB3c) = (B4aB5aB6a;B4aB5bB6b;B4bB6c;B4cB5cB6a).
    • R2: (123)^\star B^\pm\cdot(132)^\star B^\mp=1_3 or (B^\pm_{1a}B^\mp_{2a}; B^\pm_{2b}B^\mp_{3c}; B^\pm_{1c}B^\mp_{2b}) = (1;1;1).
    • R1: (B^\pm_a; B^\pm_bB^\pm_c)=(1;T^{\pm 2}).
  • But for now, skip the writing of the following relations:
    • Symmetry of Φ and of B^{\pm}.
    • u, d and \#
    • Idempotence for T, R, Φ and B^{\pm}.
    • B^{\pm} in terms of Φ and R and R in terms of T.

Exponentiation is a Miracle

  • Description of the problem.
  • Beads and strands.
  • The perturbative approach, linearization.
  • The syzygies: relations between the errors.
  • The Hochschild complex and homology.