Skip to main content

All Questions

Filter by
Sorted by
Tagged with
7 votes
1 answer
386 views

Which zero-diagonal matrices contain the all-one vector in their columns' conic hull?

Let $A$ be a non-negative zero-diagonal invertible matrix. Which $A$ make the following assertions true, which are all equivalent: The all-one vector $j$ is contained in the conic hull of $col(A)$. ...
bodhisat's user avatar
2 votes
1 answer
1k views

What does the basis of the null space of the constraint matrix of a flow problem look like?

Consider a directed graph $G=(V,\mathbb{A})$ and a set of flow constraints of the following form: $$ \sum_{(u,v)\in\mathbb{A}}x_{u,v} - \sum_{(v,u)\in \mathbb{A}}x_{v,u} = 0 \forall v \in V$$ ...
Ricardo's user avatar
  • 31