TY  - JOUR
AU  - Andrea Sorbi
TI  - Comparing $∏^0_2$ sets of the Baire space by means of general recursive operators
JO  - Fundamenta Mathematicae
PY  - 1991
SP  - 1
EP  - 12
VL  - 138
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/articles/10.4064/fm-138-1-1-12/
DO  - 10.4064/fm-138-1-1-12
LA  - en
ID  - 10_4064_fm_138_1_1_12
ER  -