On Hopf monoids in duoidal categories
  Aguiar and Mahajan's bimonoids A in a duoidal category M are studied. Under certain assumptions on M, the Fundamental Theorem of Hopf Modules is shown to hold for A if and only if the unit of A determines an A-Galois extension. Our findings are applied to the particular examples of small groupoids and of Hopf algebroids over a commutative base algebra. 
Gabriella B\"ohm, Yuanyuan Chen, Liangyun Zhang
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