Reply to RD Reynolds and JE Leklem

RD-flatness and RD-injectivity

It is proved that every commutative ring whose RD-injective modules are Σ-RD-injective is the product of a pure semi-simple ring and a finite ring. A complete characterization of commutative rings for which each artinian (respectively simple) module is RD-injective, is given. These results can be obtained by using the properties of RD-flat modules and RD-coflat modules which are respectively th...

Solutions to the 63 rd

A3 Note that each of the sets {1}, {2}, . . . , {n} has the desired property. Moreover, for each set S with integer average m that does not contain m, S ∪ {m} also has average m, while for each set T of more than one element with integer average m that contains m, T \{m} also has average m. Thus the subsets other than {1}, {2}, . . . , {n} can be grouped in pairs, so Tn −n is even. A4 (partly d...

The Authors’ Reply

The Authors’ Reply

Reply to Collignon and

TO THE EDITOR—We read with interest the correspondence from Collignon and Kennedy [1] regarding the duration of carriage of resistant bacteria after travelers return from tropical regions. The authors discussed the divergence in duration using a study they published in 2010 [2] and the VOYAG-R study [3]. While the overall design of both studies is similar, some key points are not. Importantly, ...