From the octagon to the SFT vertex - gluing and multiple wrapping

Understand

We compare various ways of decomposing and decompactifying the string field theory vertex and analyze the relations between them.

• We formulate axioms for the octagon and show how it can be glued to reproduce the decompactified pp-wave SFT vertex which in turn can be glued to recover the exact finite volume pp-wave Neumann coefficients.
• The gluing is performed by resumming multiple wrapping corrections.
• We observe important nontrivial contributions at the multiple wrapping level which are crucial for obtaining the exact results.