∑ZWMath CoursesSyllabusExercises
ES
ZWMath›Enumerative combinatorics›Posets and lattices›Lattice or order theory›ZW-LATTICE-OR-ORDER-THEORY-010
Course menu
AreaCombinatoricsCourseEnumerative combinatoricsTopicPosets and lattices
Generating functions3
  • Multinomial coefficient
  • Exponential generating function
  • Binomial coefficient Discrete mathematics
Classical combinatorial numbers7
  • Stirling number of the second kind
  • Bell number
  • Stirling number of the first kind
  • Catalan number
  • Derangement
  • Cycle of a permutation Modern algebra I
  • Inclusion-exclusion principle Discrete mathematics
Compositions and partitions4
  • Integer composition
  • Integer partition
  • Partition generating function
  • Pentagonal number theorem
Symmetry and counting2
  • Burnside's lemma
  • Orbit and stabilizer Modern algebra I
Posets and lattices2
  • Lattice or order theory
  • Partial order relation Discrete mathematics
Extremal combinatorics1
  • Steiner triple system

Exercise · ZW-LATTICE-OR-ORDER-THEORY-010 · ★★★ Advanced

How many divisors of 360 have a pair with 12 whose infimum is 4?

Choose one option.

Show answer
  • B. 4

← Back to the question

Explanation

There are four divisors of 360 whose gcd with 12 is 4.

Study Enumerative combinatorics in ZWMath →

Review the concept: Lattice or order theory

A lattice is a partially ordered set (L, ≤) in which every pair of elements x and y has a supremum (x ∨ y) and an infimum (x ∧ y).

\[x \vee y = \sup\{x,y\}, \quad x \wedge y = \inf\{x,y\}\]

More practice problems: lattice or order theory

  • ZW-LATTICE-OR-ORDER-THEORY-001 What is the supremum of 4 and 6 in the poset of divisors of 12 ordered by divisibility?
  • ZW-LATTICE-OR-ORDER-THEORY-002 In the poset of divisors of 12 ordered by divisibility, what is 4 wedge (4 vee 6)?
  • ZW-LATTICE-OR-ORDER-THEORY-003 In a lattice, what name is given to the operation x ∨ y?
  • ZW-LATTICE-OR-ORDER-THEORY-004 In the poset of subsets of \1,2,3\ ordered by inclusion, what is \1,2\ vee \2,3\?
  • ZW-LATTICE-OR-ORDER-THEORY-005 What is the supremum of 2 and 3 in the poset of divisors of 6 ordered by divisibility?
  • ZW-LATTICE-OR-ORDER-THEORY-006 In the poset of divisors of 30 ordered by divisibility, compute 6 wedge 10.
  • ZW-LATTICE-OR-ORDER-THEORY-007 In the poset of divisors of 60 ordered by divisibility, compute 10 vee 15.
  • ZW-LATTICE-OR-ORDER-THEORY-008 In the poset L=\hat0,a,b,c,hat1\ with hat0<a,b<c<hat1, what is a wedge b?

← ZW-LATTICE-OR-ORDER-THEORY-009

Practice

⏱Exam simulator10 random questions with a grade☰All exercises
◉Open on course✦Open on free study↗Open on the map

ZWMath · Math from definition to practice. Open the interactive map · Syllabus · All exercises

Author: ORCID iD 0009-0009-8641-3511

Privacy · About Speedrunz · Contact