# Recent Activity

## Few subsequence sums in Z_n x Z_n ★★

**Conjecture**For every , the sequence in consisting of copes of and copies of has the fewest number of distinct subsequence sums over all zero-free sequences from of length .

Keywords: subsequence sum; zero sum

## Olson's Conjecture ★★

Author(s): Olson

**Conjecture**If is a sequence of elements from a multiplicative group of order , then there exist so that .

Keywords: zero sum

## Highly connected graphs with no K_n minor ★★★

Author(s): Thomas

**Problem**Is it true for all , that every sufficiently large -connected graph without a minor has a set of vertices whose deletion results in a planar graph?

Keywords: connectivity; minor

## The Alon-Tarsi basis conjecture ★★

Author(s): Alon; Linial; Meshulam

**Conjecture**If are invertible matrices with entries in for a prime , then there is a submatrix of so that is an AT-base.

Keywords: additive basis; matrix

## The permanent conjecture ★★

Author(s): Kahn

**Conjecture**If is an invertible matrix, then there is an submatrix of so that is nonzero.

Keywords: invertible; matrix; permanent

## The additive basis conjecture ★★★

Author(s): Jaeger; Linial; Payan; Tarsi

**Conjecture**For every prime , there is a constant (possibly ) so that the union (as multisets) of any bases of the vector space contains an additive basis.

Keywords: additive basis; matrix

## A nowhere-zero point in a linear mapping ★★★

Author(s): Jaeger

**Conjecture**If is a finite field with at least 4 elements and is an invertible matrix with entries in , then there are column vectors which have no coordinates equal to zero such that .

Keywords: invertible; nowhere-zero flow

## Partitioning edge-connectivity ★★

Author(s): DeVos

**Question**Let be an -edge-connected graph. Does there exist a partition of so that is -edge-connected and is -edge-connected?

Keywords: edge-coloring; edge-connectivity

## Acyclic edge-colouring ★★

Author(s): Fiamcik

**Conjecture**Every simple graph with maximum degree has a proper -edge-colouring so that every cycle contains edges of at least three distinct colours.

Keywords: edge-coloring

## Packing T-joins ★★

Author(s): DeVos

**Conjecture**There exists a fixed constant (probably suffices) so that every graft with minimum -cut size at least contains a -join packing of size at least .

## Decomposing eulerian graphs ★★★

Author(s):

**Conjecture**If is a 6-edge-connected Eulerian graph and is a 2-transition system for , then has a compaible decomposition.

## Faithful cycle covers ★★★

Author(s): Seymour

**Conjecture**If is a graph, is admissable, and is even for every , then has a faithful cover.

## (m,n)-cycle covers ★★★

Author(s): Celmins; Preissmann

**Conjecture**Every bridgeless graph has a (5,2)-cycle-cover.

## Unit vector flows ★★

Author(s): Jain

**Conjecture**For every graph without a bridge, there is a flow .

**Conjecture**There exists a map so that antipodal points of receive opposite values, and so that any three points which are equidistant on a great circle have values which sum to zero.

Keywords: nowhere-zero flow

## A homomorphism problem for flows ★★

Author(s): DeVos

**Conjecture**Let be abelian groups and let and satisfy and . If there is a homomorphism from to , then every graph with a B-flow has a B'-flow.

Keywords: homomorphism; nowhere-zero flow; tension

## The three 4-flows conjecture ★★

Author(s): DeVos

**Conjecture**For every graph with no bridge, there exist three disjoint sets with so that has a nowhere-zero 4-flow for .

Keywords: nowhere-zero flow

## Bouchet's 6-flow conjecture ★★★

Author(s): Bouchet

**Conjecture**Every bidirected graph with a nowhere-zero -flow for some , has a nowhere-zero -flow.

Keywords: bidirected graph; nowhere-zero flow

## Jaeger's modular orientation conjecture ★★★

Author(s): Jaeger

**Conjecture**Every -edge-connected graph can be oriented so that (mod ) for every vertex .

Keywords: nowhere-zero flow; orientation