## On lattices equivalent to their duals.(English)Zbl 0810.11041

The authors call a lattice in Euclidean $$n$$-space isodual if it is isometric to its dual. A lattice similar to its dual (e.g., any for $$n=2$$) can be rescaled to become isodual, and certain even lattices similar to their duals (interesting from the point of view of modular forms) hold the sphere packing records for $$n=4$$, 8, 12, 16, 24, 32 and 48. The present paper, however, mainly deals with the case $$n=3$$: using their version of the Selling parameters to describe cubic lattices, the authors find that a “mean” of the face-centered and body-centered cubic lattices (called the m.c.c. lattice) solves both the isodual packing and covering problems. The paper also lists the densest isodual lattices known for $$n= 5$$, 6, 7, 9, 10, 11 and 14.

### MSC:

 11H31 Lattice packing and covering (number-theoretic aspects) 11H06 Lattices and convex bodies (number-theoretic aspects) 52C07 Lattices and convex bodies in $$n$$ dimensions (aspects of discrete geometry)
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