# A question about stress energy tensor at junction surface

I am now reading a paper (whole paper link)which regarding construct a worm hole by cutting off the stress energy tensor and glue interior and exterior space at $$r=a$$. ‘Nevertheless, I am confused about the energy stress tensor at this junction surface,I think $$i,j$$ could choose from $$τ,\theta,\phi$$which means the curvature $$\kappa^{i}_{j}$$should have $$\phi$$component , and furthermore , the energy stress tensor’ s third component should be $$P_{\phi}$$but why the author only use $$\theta$$component, could you help me?