Spring 2007 QG Seminar Errata

John Baez

Here's a list of errors we've found in the Spring 2007 Quantum Gravity Seminar notes. If you discover any more errors, please let me know, and we'll eventually try to correct them, or at least add them to this list.

Quantization and Cohomology

• Week 19 - At the bottom of page 2, the condition that a homotopy H be "thin" is that rank dH ≤ 1. In simple terms, this means that the homotopy sweeps out no area.

  In the last commutative diagram on page 5,

  Mor(C) _s×_t Mor(C)
  should be
  Mor(C) _t×_s Mor(C)
  Of course this depends on the order in which we write composition of morphisms, but right now we're using the order in which fg is the composite of a morphism f: x → y and a morphism g: y → z, so the target of the first one matches the source of the second.

Classical versus Quantum Computation

• Week 20 - On page 10, the coordinates x_i of a point in the standard simplex should sum to 1, not 0.

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