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Arindam Mazumdar coauthored a particle-physics study asking whether internal consistency of a grand unified theory can constrain the number of fermion generations. The work examines representation content and unification conditions in candidate gauge models rather than treating the number of generations only as an externally selected parameter.^[ref]

A consistency condition within one model is a conditional theoretical prediction. It does not establish that the chosen gauge structure has been experimentally realized.

Authors: Pritibhajan Byakti, David Emmanuel-Costa, Arindam Mazumdar and Palash B. Pal.

Official publication: link.springer.com/article/10.1140/epjc/s10052-014-2730-9

Section 3 gives the Standard Model branching rules of the $SU(6)$ representations $\overline{6}$ and $15$. Their cubic gauge anomaly coefficients are $-1$ and $2$, respectively; one $15$ with two $\overline{6}$ therefore cancels this gauge anomaly. Additional charged fermions can form a vectorlike gauge spectrum with invariant mass terms.