On the Axiomatizability of Certain Classes of Modules.
On the planarity of the equilateral, isogonal pentagon.
On the structure and classification of SOMAs: Generalizations of mutually orthogonal Latin squares.
Order with successors is not interprétable in RCF
Using the monotonicity theorem of L. van den Dries for RCF-definable real functions, and a further result of that author about RCF-definable equivalence relations on ℝ, we show that the theory of order with successors is not interpretable in the theory RCF. This confirms a conjecture by J. Mycielski, P. Pudlák and A. Stern.
Orthogonality as single primitive notion for metric planes.