1. Introduction

  2. S-matrix as a functor

    1. The *-category of Hilbert spaces

    2. The monoidal *-category of Hilbert spaces and its counterpart at the level of nCob

    3. TQFT as a functor

    4. The situation is in TGD framework

  3. Some general ideas

    1. Operads, number theoretical braids, and inclusions of HFFs

    2. Generalized Feynman diagram as category?

  4. Planar operads, the notion of finite measurement resolution, and arrow of geometric time

    1. Zeroth order heuristics about zero energy states

    2. Planar operads

    3. Planar operads and zero energy states

    4. Relationship to ordinary Feynman diagrammatics

  5. Category theory and symplectic QFT

    1. Fusion rules

    2. Symplectic diagrams

    3. A couple of questions inspired by the analogy with conformal field theories

    4. Associativity conditions and braiding

    5. Finite-dimensional version of the fusion algebra

  6. Could operads allow the formulation of the generalized Feynman rules?

    1. How to combine conformal fields with symplectic fields?

    2. Symplecto-conformal fields in Super Kac-Moody sector

    3. The treatment of four-momentum

    4. What does the improvement of measurement resolution really mean?

    5. How do the operads formed by generalized Feynman diagrams and symplecto-conformal fields relate?

  7. Possible other applications of category theory

    1. Categorification and finite measurement resolution

    2. Inclusions of HFFs and planar tangles

    3. 2-plectic structures and TGD

    4. TGD variant for the category nCob

    5. Number theoretical universality and category theory

    6. Category theory and fermionic parts of zero energy states as logical deductions

    7. Category theory and hierarchy of Planck constants