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- complete upper bounds connected by a constant – by definition
- complete upper bounds cluster by a constant – by definition
- tree upper bounds connected by a constant – by definition
- tree upper bounds forest by a constant – by definition
- path upper bounds connected by a constant – by definition
- path upper bounds linear forest by a constant – by definition
- star upper bounds connected by a constant – by definition
- star upper bounds stars by a constant – by definition
- cycle upper bounds connected by a constant – by definition
- cycle upper bounds cycles by a constant – by definition
- block – Every block (maximal 2-connected subgraph) is a clique.
- cluster – Disjoint union of complete graphs.
- cluster – Every connected component is a complete graph.
- cluster – Does not include path on three vertices as an induced subgraph.
- co-cluster – Complete multipartite graph.
- disjoint cycles – All cycles in the graph are disjoint. Can contain arbitrary trees attached to and between the cycles.
- pathwidth+maxdegree $k$ upper bounds pathwidth by $\mathcal O(k)$ – by definition
- pathwidth+maxdegree $k$ upper bounds maximum degree by $\mathcal O(k)$ – by definition
- degree treewidth $k$ upper bounds maximum degree by $\mathcal O(k)$ – by definition
- degree treewidth $k$ upper bounds treewidth by $\mathcal O(k)$ – by definition
- complete upper bounds distance to complete by a constant – by definition
- co-cluster upper bounds distance to co-cluster by a constant – by definition
- cograph upper bounds distance to cograph by a constant – by definition
- cluster upper bounds distance to cluster by a constant – by definition
- linear forest upper bounds distance to linear forest by a constant – by definition
- outerplanar upper bounds distance to outerplanar by a constant – by definition
- block upper bounds distance to block by a constant – by definition
- edgeless upper bounds distance to edgeless by a constant – by definition
- forest upper bounds distance to forest by a constant – by definition
- bipartite upper bounds distance to bipartite by a constant – by definition
- planar upper bounds distance to planar by a constant – by definition
- chordal upper bounds distance to chordal by a constant – by definition
- stars upper bounds distance to stars by a constant – by definition
- perfect upper bounds distance to perfect by a constant – by definition
- interval upper bounds distance to interval by a constant – by definition
- maximum degree $k$ upper bounds distance to maximum degree by $\mathcal O(k)$ – by definition
- bounded components $k$ upper bounds distance to bounded components by $\mathcal O(k)$ – by definition
- disconnected upper bounds distance to disconnected by a constant – by definition
- maximum matching on bipartite graphs $k$ upper bounds bipartite by $\mathcal O(k)$ – by definition
- maximum matching on bipartite graphs $k$ upper bounds maximum matching by $\mathcal O(k)$ – by definition
- linear forest – Disjoint union of paths.
- maximum matching on bipartite graphs $k$ implies that vertex cover is $\mathcal O(k)$ – KÅ‘nig’s theorem
- vertex cover $k$ implies that maximum matching is $\mathcal O(k)$ – Every edge of the matching needs to be covered by at least one vertex. Path shows lower bound.
- odd cycle transversal is equal to distance to bipartite – Bipartite graphs is the graph class without any odd cycles.
- feedback edge set $k$ upper bounds feedback vertex set by $\mathcal O(k)$ – Given solution to feedback edge set one can remove one vertex incident to the solution edges to obtain feedback vertex set.
- feedback edge set $k$ upper bounds genus by $\mathcal O(k)$ – Removing $k$ edges creates a forest that is embeddable into the plane. We now add one handle for each of the $k$ edges to get embedding into $k$-handle genus.
- chromatic number $k$ upper bounds maximum clique by $\mathcal O(k)$ – Unbounded clique implies the number of needed colors is unbounded.
- degeneracy $k$ upper bounds chromatic number by $\mathcal O(k)$ – Greedily color the vertices in order of the degeneracy ordering. As each vertex has at most $k$ colored predecesors we use at most $k+1$ colors.
- degeneracy $k$ upper bounds average degree by $\mathcal O(k)$ – Removing a vertex of degree $d$ increases the value added to the sum of all degrees by at most $2d$, hence, the average is no more than twice the degeneracy.
- maximum degree $k$ upper bounds h-index by $\mathcal O(k)$ – As h-index seeks $k$ vertices of degree $k$ it is trivially upper bound by maximum degree.
- minimum degree $k$ upper bounds edge connectivity by $\mathcal O(k)$ – Removing edges incident to the minimum degree vertex disconnects the graph.
- linear rank-width $k$ upper bounds rank-width by $f(k)$
- pathwidth $k$ upper bounds linear rank-width by $f(k)$
- minimum degree $k$ upper bounds domatic number by $\mathcal O(k)$ – The vertex of minimum degree needs to be dominated in each of the sets. As the sets cannot overlap there can be at most $k+1$ of them.
- distance to linear forest $k$ upper bounds pathwidth by $\mathcal O(k)$ – After removal of $k$ vertices the remaining class has a bounded width $w$. So by including the removed vertices in every bag, we can achieve decomposition of width $w+k$
- topological bandwidth $k$ upper bounds bisection bandwidth by $\mathcal O(k)$ – Order vertices by their bandwidth integer. We split the graph in the middle of this ordering. There are at most roughly $k^2/2$ edges over this split.
- bandwidth $k$ upper bounds maximum degree by $\mathcal O(k)$ – Each vertex has an integer $i$ and may be connected only to vertices whose difference from $i$ is at most $k$. There are at most $k$ bigger and $k$ smaller such neighbors.
- distance to linear forest $k$ upper bounds pathwidth by $\mathcal O(k)$ – After removal of $k$ vertices the remaining class has a bounded width $w$. So by including the removed vertices in every bag, we can achieve decomposition of width $w+k$
- distance to outerplanar $k$ upper bounds treewidth by $\mathcal O(k)$ – After removal of $k$ vertices the remaining class has a bounded width $w$. So by including the removed vertices in every bag, we can achieve decomposition of width $w+k$
- vertex integrity $k$ upper bounds treedepth by $\mathcal O(k)$ – First, treedepth removes vertices of the modulator, then it iterates through remaining components one by one.
- distance to stars $k$ upper bounds treedepth by $\mathcal O(k)$ – First, treedepth removes vertices of the modulator, remainder has treedepth $2$
- distance to complete $k$ upper bounds clique cover number by $\mathcal O(k)$ – We cover the $k$ vertices of the modulator by cliques of size $1$ and cover the remaining clique by another one.
- maximum independent set $k$ upper bounds domination number by $\mathcal O(k)$ – Every maximal independent set is also a dominating set because any undominated vertex could be added to the independent set.
- domination number $k$ upper bounds diameter by $\mathcal O(k)$ – An unbounded diameter implies a long path where no vertices that are more than $3$ apart may be dominated by the same dominating vertex, otherwise we could shorten the path. Hence, the number of dominating vertices is also unbounded.
- distance to bipartite $k$ upper bounds chromatic number by $\mathcal O(k)$ – Removed vertices get one color each and we need only $2$ colors for the rest.
- edge clique cover number $k$ upper bounds neighborhood diversity by $2^{\mathcal O(k)}$ – Label vertices by the cliques they are contained in, each label is its own group in the neighborhood diversity, connect accordingly.
- distance to complete $k$ upper bounds edge clique cover number by $k^{\mathcal O(1)}$ – Cover the remaining clique, cover each modulator vertex and its neighborhood outside of it with another clique, cover each edge within the modulator by its own edge.
- treewidth $k$ upper bounds book thickness by $f(k)$
- maximum leaf number $k$ upper bounds distance to linear forest by $f(k)$
- acyclic chromatic number $k$ upper bounds boxicity by $f(k)$
- h-index $k$ upper bounds distance to maximum degree by $\mathcal O(k)$ – Remove the $h$ vertices of degree at least $h$ to get a graph that has maximum degree $h$.
- distance to maximum degree $k$ upper bounds h-index by $\mathcal O(k)$ – Removal of $k$ vertices yielding a graph with maximum degree $c$ means that there were $k$ vertices of arbitrary degree and the remaining vertices had degree at most $k+c$. Hence, $h$-index is no more than $k+c$.
- vertex connectivity is equal to distance to disconnected – By definition
- distance to cograph $k$ upper bounds clique-width by $f(k)$
- distance to cograph $k$ upper bounds chordality by $f(k)$
- distance to cograph $k$ upper bounds diameter by $f(k)$
- book thickness $k$ upper bounds acyclic chromatic number by $f(k)$
- average distance $k$ upper bounds girth by $f(k)$
- maximum leaf number $k$ upper bounds feedback edge set by $f(k)$
- maximum induced matching $k$ upper bounds diameter by $\mathcal O(k)$ – Diameter requires an induced path on $d$ edges, hence, maximum induced matching is at least $\lfloor (d+1)/3 \rfloor$.
- maximum independent set $k$ upper bounds maximum induced matching by $\mathcal O(k)$ – Each edge of the induced matching can host at one vertex of the independent set.
- vertex cover $k$ upper bounds neighborhood diversity by $2^{\mathcal O(k)}$
- bounded twin-cover number does not imply bounded neighborhood diversity
- twin-cover number $k$ upper bounds shrub-depth by $\mathcal O(k)$
- linear clique-width $k$ upper bounds clique-width by $f(k)$
- clique-width $k$ upper bounds boolean width by $\mathcal O(k)$
- boolean width $k$ upper bounds clique-width by $2^{\mathcal O(k)}$
- branch width $k$ upper bounds boolean width by $\mathcal O(k)$
- branch width $k$ upper bounds rank-width by $\mathcal O(k)$
- treewidth $k$ upper bounds boolean width by $f(k)$
- bandwidth $k$ implies that cutwidth is $k^{\mathcal O(1)}$ – Any bandwidth bound cutwidth quadratically. An example where this happens is $(P_n)^k$ which has bandwidth $k$ and cutwidth $O(k^2)$; both seem to be optimal.
- modular-width $k$ upper bounds clique-width by $f(k)$
- modular-width $k$ upper bounds diameter by $f(k)$
- maximum degree $k$ upper bounds c-closure by $f(k)$
- feedback edge set $k$ upper bounds c-closure by $f(k)$
- vertex integrity $k$ upper bounds distance to bounded components by $\mathcal O(k)$ – By definition
- distance to bounded components $k$ upper bounds vertex integrity by $\mathcal O(k)$ – By definition
- bandwidth $k$ upper bounds topological bandwidth by $\mathcal O(k)$ – By definition
- twin-cover number $k$ upper bounds distance to cluster by $\mathcal O(k)$ – By definition
- vertex cover $k$ upper bounds twin-cover number by $\mathcal O(k)$ – By definition
- average degree $k$ upper bounds minimum degree by $\mathcal O(k)$ – By definition
- diameter $k$ upper bounds average distance by $\mathcal O(k)$ – By definition
- maximum matching $k$ upper bounds maximum induced matching by $\mathcal O(k)$ – By definition
- distance to interval $k$ upper bounds boxicity by $\mathcal O(k)$ – By definition
- bisection bandwidth $k$ upper bounds edge connectivity by $\mathcal O(k)$ – By definition
- vertex integrity – Minimum $k$ such that there exists $k$ vertices whose removal results in connected components of sizes at most $k$.
- twin-cover number – Distance to cluster where all vertices of each clique are siblings.
- maximum degree – maximum degree of graph’s vertices
- feedback vertex set – can be thought of as a distance to forest
- minimum degree – minimum degree of graph’s vertices
- diameter – Maximum distance of two vertices that are in the same connected component.
- treedepth $k$ upper bounds diameter by $f(k)$ – An unbounded diameter implies the class contains paths as subgraphs. Minimum treedepth to embed a path of length $n$ in a treedepth tree is $\log n$.
- feedback vertex set is equal to distance to forest
- vertex cover is equal to distance to edgeless
- graph class complete has unbounded maximum clique – Parameter is unbounded for the graph class of cliques.
- graph class complete has unbounded domatic number – Parameter is unbounded for the graph class of cliques.
- graph class complete has unbounded edge connectivity – Parameter is unbounded for the graph class of cliques.
- graph class co-cluster has unbounded distance to chordal
- cluster upper bounds twin-cover number by a constant
- graph class cluster has unbounded domination number
- graph class bipartite has unbounded girth
- graph class bipartite has unbounded edge connectivity
- forest upper bounds feedback edge set by a constant
- graph class forest has unbounded girth
- graph class forest has unbounded distance to interval
- edgeless upper bounds vertex cover by a constant
- graph class edgeless has unbounded domination number
- graph class grid has unbounded distance to chordal
- graph class grid has unbounded average distance
- graph class grid has unbounded bisection bandwidth
- disjoint cycles upper bounds bisection bandwidth by a constant
- outerplanar upper bounds bisection bandwidth by a constant
- grid upper bounds maximum degree by a constant
- graph class disjoint cycles has unbounded girth
- graph class interval has unbounded average distance
- graph class path has unbounded treedepth
- graph class linear forest has unbounded average distance
- planar upper bounds genus by a constant
- graph class planar has unbounded girth
- graph class planar has unbounded maximum degree
- graph class planar has unbounded distance to perfect
- bounded vertex integrity does not imply bounded neighborhood diversity
- graph class stars has unbounded h-index
- graph class stars has unbounded vertex integrity
- graph class disjoint cycles has unbounded distance to perfect
- cycle upper bounds maximum leaf number by a constant
- graph class cycle has unbounded girth
- maximum leaf number $k$ upper bounds feedback edge set by $k^{\mathcal O(1)}$ – M. Bentert (personal communication)
- bounded components $k$ upper bounds cutwidth by $k^{\mathcal O(1)}$ – By greedily placing one component after another.
- bounded bounded components does not imply bounded distance to perfect – By a disjoint union of small components with distance to perfect at least 1.
- bounded bounded components does not imply bounded distance to planar – By a disjoint union of many $K_5$ graphs.
- edgeless upper bounds bounded components by a constant – By definition
- grid upper bounds maximum degree by a constant – By definition
- bounded components $k$ upper bounds maximum degree by $\mathcal O(k)$ – By definition
- linear forest upper bounds maximum degree by a constant – By definition
- cycles upper bounds maximum degree by a constant – By definition