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Bose statistics is the symmetric exchange statistics of identical bosons. Commuting creation operators build the symmetric bosonic Fock space; a normalized one-particle mode has occupation states $(a^{†}{)}^n|0⟩/\sqrt{n!}$ for every nonnegative integer $n$. At thermal equilibrium these statistics lead to the Bose-Einstein distribution. Exchange symmetry itself does not require thermal equilibrium.

Each of $D$ embedding bosons contributes one to the chiral central charge, and each real worldsheet Majorana fermion contributes one half. The reparameterization bc system contributes $-26$, and the superconformal ghosts contribute $+11$. Vanishing total worldsheet Weyl anomaly therefore requires $3D/2-26+11=0$, or $D=10$. This differs from the critical dimension 26 of the bosonic string, which has no worldsheet fermions or superconformal ghosts.

Each of $d$ physical transverse bosons with a Neumann-Dirichlet open-string boundary condition contributes $\frac{1}{2}{\sum }_{r>0}r=1/48$ by the half-integer zeta-regularized mode sum. Thus $L_0^{\perp }=N+d/48$ and the convention $L_0={\alpha }^{\prime }{p}^2+N-a$ has $a=-d/48$. For $d=24$, the vacuum shift is $+1/2$. The ordinary integer-moded open-string shift is instead $-d/24$; these endpoint sectors have different normal-ordering constants.