number of 4 cycles

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Let $C_4$ be a cycle with $4$ vertices. For an arbitrary graph $G$ with $n$ vertices and m edges say $m>nsqrt n$, how many $C_4$s exist? Is there a lower bound for this?










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    Let $C_4$ be a cycle with $4$ vertices. For an arbitrary graph $G$ with $n$ vertices and m edges say $m>nsqrt n$, how many $C_4$s exist? Is there a lower bound for this?










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      favorite









      up vote
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      down vote

      favorite











      Let $C_4$ be a cycle with $4$ vertices. For an arbitrary graph $G$ with $n$ vertices and m edges say $m>nsqrt n$, how many $C_4$s exist? Is there a lower bound for this?










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      Let $C_4$ be a cycle with $4$ vertices. For an arbitrary graph $G$ with $n$ vertices and m edges say $m>nsqrt n$, how many $C_4$s exist? Is there a lower bound for this?







      graph-theory graph-minor






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      shahrzad haddadan

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          Yes, this is known. For $d = Omega(n^1/2)$ with a sufficiently large implicit constant, any $n$-node graph of average degree $d$ has $Omega(d^4)$ total $C_4$s.
          This is best possible because it's realized by a random graph.



          The earliest reference I'm aware of for this is "Cube-Supersaturated Graphs and Related Problems" by Erdos and Simonovits, where it's claimed without proof. There are many proofs out there, off the top of my head see Lemma 3 here.






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            Yes, this is known. For $d = Omega(n^1/2)$ with a sufficiently large implicit constant, any $n$-node graph of average degree $d$ has $Omega(d^4)$ total $C_4$s.
            This is best possible because it's realized by a random graph.



            The earliest reference I'm aware of for this is "Cube-Supersaturated Graphs and Related Problems" by Erdos and Simonovits, where it's claimed without proof. There are many proofs out there, off the top of my head see Lemma 3 here.






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              up vote
              3
              down vote













              Yes, this is known. For $d = Omega(n^1/2)$ with a sufficiently large implicit constant, any $n$-node graph of average degree $d$ has $Omega(d^4)$ total $C_4$s.
              This is best possible because it's realized by a random graph.



              The earliest reference I'm aware of for this is "Cube-Supersaturated Graphs and Related Problems" by Erdos and Simonovits, where it's claimed without proof. There are many proofs out there, off the top of my head see Lemma 3 here.






              share|cite|improve this answer
























                up vote
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                up vote
                3
                down vote









                Yes, this is known. For $d = Omega(n^1/2)$ with a sufficiently large implicit constant, any $n$-node graph of average degree $d$ has $Omega(d^4)$ total $C_4$s.
                This is best possible because it's realized by a random graph.



                The earliest reference I'm aware of for this is "Cube-Supersaturated Graphs and Related Problems" by Erdos and Simonovits, where it's claimed without proof. There are many proofs out there, off the top of my head see Lemma 3 here.






                share|cite|improve this answer














                Yes, this is known. For $d = Omega(n^1/2)$ with a sufficiently large implicit constant, any $n$-node graph of average degree $d$ has $Omega(d^4)$ total $C_4$s.
                This is best possible because it's realized by a random graph.



                The earliest reference I'm aware of for this is "Cube-Supersaturated Graphs and Related Problems" by Erdos and Simonovits, where it's claimed without proof. There are many proofs out there, off the top of my head see Lemma 3 here.







                share|cite|improve this answer














                share|cite|improve this answer



                share|cite|improve this answer








                edited 1 hour ago

























                answered 1 hour ago









                GMB

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