Vectors of matroids over tracts
  We enrich Baker and Bowler's theory of matroids over tracts with notions of vectors and covectors. In the case of oriented matroids, these $F$-vectors and $F$-covectors coincide with the usual signed vectors and signed covectors. In the case of matroids over a field $F$, the $F$-covector set resp. $F$-vector set of an $F$-matroid is a linear subspace of $F^E$ resp. its orthogonal complement. 
Laura Anderson
math.CO math.AG math.RA