This is an investigation of the role of shuffling and concatenating in the
theory of graph drawing. A simple syntactic description of these and related
operations is proved complete in the context of finite partial orders, as
general as possible. An explanation based on that is given for a previously
investigated collapse of the permutohedron into the associahedron, and for
collapses into other less familiar polyhedra, including the cyclohedron.
The goal of this paper is to prove coherence results with respect to
relational graphs for monoidal endofunctors, i.e. endofunctors of a monoidal
category that preserve the monoidal structure up to a natural transformation
that need not be an isomorphism. These results are proved first in the absence
of symmetry in the monoidal structure, and then with this symmetry.
The goal of this paper is to prove coherence results with respect to
relational graphs for monoidal monads and comonads, i.e. monads and comonads in
a monoidal category such that the endofunctor of the monad or comonad is a
monoidal functor (this means that it preserves the monoidal structure up to a
natural transformation that need not be an isomorphism). These results are
proved first in the absence of symmetry in the monoidal structure, and then
with this symmetry. The monoidal structure is also allowed to be given with
finite products or finite coproducts.
Isomorphism between formulae is defined with respect to categories
formalizing equality of deductions in classical propositional logic and in the
multiplicative fragment of classical linear propositional logic caught by proof
nets. This equality is motivated by generality of deductions. Characterizations
are given for pairs of isomorphic formulae, which lead to decision procedures
for this isomorphism.