Problem 10
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We define a dogma as a right-cancellative magma \((D,\star)\) with the property that
\[ (x \star y) \star y = y \star x \qquad \text{for all } x,y \in D. \]
- Find a dogma of cardinality \(1881\).
- For which \(n\) does there exist a dogma of cardinality \(n\)?
Source: Ma Li.
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We define a "dogma" as a right-cancellative magma $(D, \star)$ with the property that $(x \star y) \star y = y \star x$ for all $x, y \in D$. 1. Find a dogma of cardinality $1881$. 2. For which $n$ does there exist a dogma of cardinality $n$?
Added June 22, 2026.