The second-order monadic theory of the free inverse monoid is undecidable. (La théorie monadique du second ordre du monoïde inversif libre est indécidable.)
Calbrix, Hugues
Bulletin of the Belgian Mathematical Society - Simon Stevin, Tome 4 (1997), p. 53-65 / Harvested from The Electronic Library of Mathematics
Full (PDF)
Publié le : 1997-01-01
EUDML-ID : urn:eudml:doc:119754 
@article{01260654,
     title = {The second-order monadic theory of the free inverse monoid is undecidable. (La th\'eorie monadique du second ordre du mono\"\i de inversif libre est ind\'ecidable.)},
     journal = {Bulletin of the Belgian Mathematical Society - Simon Stevin},
     volume = {4},
     year = {1997},
     pages = {53-65},
     zbl = {0913.03017},
     language = {en},
     url = {http://dml.mathdoc.fr/item/01260654}
}

Calbrix, Hugues. The second-order monadic theory of the free inverse monoid is undecidable. (La théorie monadique du second ordre du monoïde inversif libre est indécidable.). Bulletin of the Belgian Mathematical Society - Simon Stevin, Tome 4 (1997) pp. 53-65. http://gdmltest.u-ga.fr/item/01260654/