proof of theorem: if $G$ is a graph in which all its cycle lengths are divisible by 4, then $sq(G) le...












0












$begingroup$


Theorem: If $G$ is a graph in which all its cycle lengths are divisible by 4, then $sq(G) le Delta^2(G)$.



$sq(G)$ denote strong chromatics index and $Delta(G)$ denote maximum degree of graph $G$



Proof of this theorem is by induction on $|E(G)|$.



In base step $|E(G)|=1$, then $sq(G)=1$ and $Delta^2(G)=1$



In inductive step we assume that: for any graph $H$ with $m$ edges $sq(H)le Delta^2(H)$



inductive hypothesis: for any graph $G$ with $m+1$ edges $sq(G)le Delta^2(G)$.



How can I prove inductive step?










share|cite|improve this question









$endgroup$












  • $begingroup$
    What have you tried for the induction? Have you looked at minors of $G$, edge contraction, edge deletion? removing a (non-isolated) vertex?
    $endgroup$
    – Thomas Lesgourgues
    Jan 26 at 11:15










  • $begingroup$
    Please check this paper: GYARFAS, A., & TUZA, Z. (1990). The strong chromatic index of graphs. Ars Combinatoria, 29, 205-211.
    $endgroup$
    – W.R.P.S
    Jan 27 at 8:50










  • $begingroup$
    @ThomasLesgourgues if $x$ is a vertex with degree $1$ then we can remove this vertex with incident egde
    $endgroup$
    – Kate
    Jan 27 at 16:00
















0












$begingroup$


Theorem: If $G$ is a graph in which all its cycle lengths are divisible by 4, then $sq(G) le Delta^2(G)$.



$sq(G)$ denote strong chromatics index and $Delta(G)$ denote maximum degree of graph $G$



Proof of this theorem is by induction on $|E(G)|$.



In base step $|E(G)|=1$, then $sq(G)=1$ and $Delta^2(G)=1$



In inductive step we assume that: for any graph $H$ with $m$ edges $sq(H)le Delta^2(H)$



inductive hypothesis: for any graph $G$ with $m+1$ edges $sq(G)le Delta^2(G)$.



How can I prove inductive step?










share|cite|improve this question









$endgroup$












  • $begingroup$
    What have you tried for the induction? Have you looked at minors of $G$, edge contraction, edge deletion? removing a (non-isolated) vertex?
    $endgroup$
    – Thomas Lesgourgues
    Jan 26 at 11:15










  • $begingroup$
    Please check this paper: GYARFAS, A., & TUZA, Z. (1990). The strong chromatic index of graphs. Ars Combinatoria, 29, 205-211.
    $endgroup$
    – W.R.P.S
    Jan 27 at 8:50










  • $begingroup$
    @ThomasLesgourgues if $x$ is a vertex with degree $1$ then we can remove this vertex with incident egde
    $endgroup$
    – Kate
    Jan 27 at 16:00














0












0








0





$begingroup$


Theorem: If $G$ is a graph in which all its cycle lengths are divisible by 4, then $sq(G) le Delta^2(G)$.



$sq(G)$ denote strong chromatics index and $Delta(G)$ denote maximum degree of graph $G$



Proof of this theorem is by induction on $|E(G)|$.



In base step $|E(G)|=1$, then $sq(G)=1$ and $Delta^2(G)=1$



In inductive step we assume that: for any graph $H$ with $m$ edges $sq(H)le Delta^2(H)$



inductive hypothesis: for any graph $G$ with $m+1$ edges $sq(G)le Delta^2(G)$.



How can I prove inductive step?










share|cite|improve this question









$endgroup$




Theorem: If $G$ is a graph in which all its cycle lengths are divisible by 4, then $sq(G) le Delta^2(G)$.



$sq(G)$ denote strong chromatics index and $Delta(G)$ denote maximum degree of graph $G$



Proof of this theorem is by induction on $|E(G)|$.



In base step $|E(G)|=1$, then $sq(G)=1$ and $Delta^2(G)=1$



In inductive step we assume that: for any graph $H$ with $m$ edges $sq(H)le Delta^2(H)$



inductive hypothesis: for any graph $G$ with $m+1$ edges $sq(G)le Delta^2(G)$.



How can I prove inductive step?







graph-theory






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Jan 25 at 17:10









KateKate

104




104












  • $begingroup$
    What have you tried for the induction? Have you looked at minors of $G$, edge contraction, edge deletion? removing a (non-isolated) vertex?
    $endgroup$
    – Thomas Lesgourgues
    Jan 26 at 11:15










  • $begingroup$
    Please check this paper: GYARFAS, A., & TUZA, Z. (1990). The strong chromatic index of graphs. Ars Combinatoria, 29, 205-211.
    $endgroup$
    – W.R.P.S
    Jan 27 at 8:50










  • $begingroup$
    @ThomasLesgourgues if $x$ is a vertex with degree $1$ then we can remove this vertex with incident egde
    $endgroup$
    – Kate
    Jan 27 at 16:00


















  • $begingroup$
    What have you tried for the induction? Have you looked at minors of $G$, edge contraction, edge deletion? removing a (non-isolated) vertex?
    $endgroup$
    – Thomas Lesgourgues
    Jan 26 at 11:15










  • $begingroup$
    Please check this paper: GYARFAS, A., & TUZA, Z. (1990). The strong chromatic index of graphs. Ars Combinatoria, 29, 205-211.
    $endgroup$
    – W.R.P.S
    Jan 27 at 8:50










  • $begingroup$
    @ThomasLesgourgues if $x$ is a vertex with degree $1$ then we can remove this vertex with incident egde
    $endgroup$
    – Kate
    Jan 27 at 16:00
















$begingroup$
What have you tried for the induction? Have you looked at minors of $G$, edge contraction, edge deletion? removing a (non-isolated) vertex?
$endgroup$
– Thomas Lesgourgues
Jan 26 at 11:15




$begingroup$
What have you tried for the induction? Have you looked at minors of $G$, edge contraction, edge deletion? removing a (non-isolated) vertex?
$endgroup$
– Thomas Lesgourgues
Jan 26 at 11:15












$begingroup$
Please check this paper: GYARFAS, A., & TUZA, Z. (1990). The strong chromatic index of graphs. Ars Combinatoria, 29, 205-211.
$endgroup$
– W.R.P.S
Jan 27 at 8:50




$begingroup$
Please check this paper: GYARFAS, A., & TUZA, Z. (1990). The strong chromatic index of graphs. Ars Combinatoria, 29, 205-211.
$endgroup$
– W.R.P.S
Jan 27 at 8:50












$begingroup$
@ThomasLesgourgues if $x$ is a vertex with degree $1$ then we can remove this vertex with incident egde
$endgroup$
– Kate
Jan 27 at 16:00




$begingroup$
@ThomasLesgourgues if $x$ is a vertex with degree $1$ then we can remove this vertex with incident egde
$endgroup$
– Kate
Jan 27 at 16:00










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