1 citations · 1 across the 4 of their papers we have counts for
4 papers
A composition theory for upward planar orders
Xue Dong, Xuexing Lu, Yu Ye
An upward planar order on an acyclic directed graph is a special linear extension of the edge poset of that satisfies the nesting condition. This order was introduced to co…
Combinatorial characterization of upward planarity
Xuexing Lu, Yu Ye
We give a combinatorial characterization of upward planar graphs in terms of upward planar orders, which are special linear extensions of edge posets.
A graphical calculus for semi-groupal categories
Sen Hu, Xuexing Lu, Yu Ye
Around the year 1988, Joyal and Street established a graphical calculus for monoidal categories, which provides a firm foundation for many explorations of graphical notations in ma…
Combinatorics and algebra of tensor calculus
Sen Hu, Xuexing Lu, Yu Ye
In this paper, motivated by the theory of operads and PROPs we reveal the combinatorial nature of tensor calculus for strict tensor categories and show that there exists a monad wh…