Machine-translated by Google. Questions are authored in English.
Top

Discussion

The number of non-isomorphic modular lattices on 5 elements is :

  • A.3
  • B.4
  • C.5
  • D.2

Answer: B

There are 4 non-isomorphic modular lattices on 5 elements.

There are exactly five lattices with 5 elements: the chain; the diamond \(M_{3}\) (a top, a bottom and three incomparable atoms); the pentagon \(N_{5}\); and the two lattices formed from the four-element Boolean square by adding a new top or a new bottom.

A lattice is modular unless it contains a copy of \(N_{5}\), so the pentagon is the only non-modular one. The chain and the two square-based lattices are even distributive, and \(M_{3}\) is modular but not distributive. That leaves 4 modular lattices.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.