30th international conference on Formal Power Series and Algebraic Combinatorics, FPSAC 2018, New Hampshire, United States Of America, 16 - 20 July 2018
We establish an isomorphism between the center EndHtw(1) of the twisted Heisenberg category of Cautis and Sussan and G, the subalgebra of the symmetric functions generated by odd power sums. We give a graphical description of Ivanov's factorial Schur P-functions as closed diagrams in Htw and show that the curl generators of EndHtw(1) correspond to two sets of generators of G discovered by Petrov which encode data related to up/down transition functions on the Schur graph. Our results are a twisted analogue of those of Kvinge, Licata, and Mitchell, which related the center of Khovanov's Heisenberg category to the algebra of shifted symmetric functions.