Every subsemigroup of a free semigroup with zero is not an R-semigroup.
Semigroup forum, Tome 12 (1976), pp. 380-382.

Voir la notice de l'article provenant de la source European Digital Mathematics Library

@article{SF_1976__12_134189,
     author = {H.J. Shyr},
     title = {Every subsemigroup of a free semigroup with zero is not an {R-semigroup.}},
     journal = {Semigroup forum},
     pages = {380--382},
     publisher = {mathdoc},
     volume = {12},
     year = {1976},
     zbl = {0338.20067},
     url = {http://geodesic.mathdoc.fr/item/SF_1976__12_134189/}
}
TY  - JOUR
AU  - H.J. Shyr
TI  - Every subsemigroup of a free semigroup with zero is not an R-semigroup.
JO  - Semigroup forum
PY  - 1976
SP  - 380
EP  - 382
VL  - 12
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/SF_1976__12_134189/
ID  - SF_1976__12_134189
ER  - 
%0 Journal Article
%A H.J. Shyr
%T Every subsemigroup of a free semigroup with zero is not an R-semigroup.
%J Semigroup forum
%D 1976
%P 380-382
%V 12
%I mathdoc
%U http://geodesic.mathdoc.fr/item/SF_1976__12_134189/
%F SF_1976__12_134189
H.J. Shyr. Every subsemigroup of a free semigroup with zero is not an R-semigroup.. Semigroup forum, Tome 12 (1976), pp. 380-382. http://geodesic.mathdoc.fr/item/SF_1976__12_134189/