How to check whether a convex polyhedron is contained in another convex polyhedron?

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5
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Suppose we have two convex polyhedra



$$P_1=xin mathbbR^n mid A_1 x geq b_1 $$



$$P_2=xin mathbbR^n mid A_2 x geq b_2 $$



Is there a way to check whether $P_1 subseteq P_2$? I was hoping that this can be done by solving some linear program. Is this possible?







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  • If you want to show that $P_1 subset P_2$, you have to show that $forall x in P_1 colon A_2 x geq b_2$
    – aGer
    Jun 29 '15 at 14:21











  • I wonder if you could do something with minkowski sums and minkowski portal refinement (MPR / Xenocollide) or GJK?
    – Alan Wolfe
    Jun 29 '15 at 16:39










  • @aGer I'm trying to do that by coming up with a general method using something like Farkas lemma, but no success so far. :-(
    – Tony
    Jun 29 '15 at 21:33






  • 1




    What's interesting is that there is something called the S-procedure that does something every similar to this for quadratic forms. That suggests it should be possible for affine forms, but I'll be darned if I can figure out how.
    – Michael Grant
    Jun 30 '15 at 2:04










  • What @aGer is proposing is possible, see my answer to this question.
    – LinAlg
    Jan 14 '17 at 15:04














up vote
5
down vote

favorite












Suppose we have two convex polyhedra



$$P_1=xin mathbbR^n mid A_1 x geq b_1 $$



$$P_2=xin mathbbR^n mid A_2 x geq b_2 $$



Is there a way to check whether $P_1 subseteq P_2$? I was hoping that this can be done by solving some linear program. Is this possible?







share|cite|improve this question






















  • If you want to show that $P_1 subset P_2$, you have to show that $forall x in P_1 colon A_2 x geq b_2$
    – aGer
    Jun 29 '15 at 14:21











  • I wonder if you could do something with minkowski sums and minkowski portal refinement (MPR / Xenocollide) or GJK?
    – Alan Wolfe
    Jun 29 '15 at 16:39










  • @aGer I'm trying to do that by coming up with a general method using something like Farkas lemma, but no success so far. :-(
    – Tony
    Jun 29 '15 at 21:33






  • 1




    What's interesting is that there is something called the S-procedure that does something every similar to this for quadratic forms. That suggests it should be possible for affine forms, but I'll be darned if I can figure out how.
    – Michael Grant
    Jun 30 '15 at 2:04










  • What @aGer is proposing is possible, see my answer to this question.
    – LinAlg
    Jan 14 '17 at 15:04












up vote
5
down vote

favorite









up vote
5
down vote

favorite











Suppose we have two convex polyhedra



$$P_1=xin mathbbR^n mid A_1 x geq b_1 $$



$$P_2=xin mathbbR^n mid A_2 x geq b_2 $$



Is there a way to check whether $P_1 subseteq P_2$? I was hoping that this can be done by solving some linear program. Is this possible?







share|cite|improve this question














Suppose we have two convex polyhedra



$$P_1=xin mathbbR^n mid A_1 x geq b_1 $$



$$P_2=xin mathbbR^n mid A_2 x geq b_2 $$



Is there a way to check whether $P_1 subseteq P_2$? I was hoping that this can be done by solving some linear program. Is this possible?









share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jul 25 '17 at 22:52









Rodrigo de Azevedo

12.6k41751




12.6k41751










asked Jun 29 '15 at 14:02









Tony

20129




20129











  • If you want to show that $P_1 subset P_2$, you have to show that $forall x in P_1 colon A_2 x geq b_2$
    – aGer
    Jun 29 '15 at 14:21











  • I wonder if you could do something with minkowski sums and minkowski portal refinement (MPR / Xenocollide) or GJK?
    – Alan Wolfe
    Jun 29 '15 at 16:39










  • @aGer I'm trying to do that by coming up with a general method using something like Farkas lemma, but no success so far. :-(
    – Tony
    Jun 29 '15 at 21:33






  • 1




    What's interesting is that there is something called the S-procedure that does something every similar to this for quadratic forms. That suggests it should be possible for affine forms, but I'll be darned if I can figure out how.
    – Michael Grant
    Jun 30 '15 at 2:04










  • What @aGer is proposing is possible, see my answer to this question.
    – LinAlg
    Jan 14 '17 at 15:04
















  • If you want to show that $P_1 subset P_2$, you have to show that $forall x in P_1 colon A_2 x geq b_2$
    – aGer
    Jun 29 '15 at 14:21











  • I wonder if you could do something with minkowski sums and minkowski portal refinement (MPR / Xenocollide) or GJK?
    – Alan Wolfe
    Jun 29 '15 at 16:39










  • @aGer I'm trying to do that by coming up with a general method using something like Farkas lemma, but no success so far. :-(
    – Tony
    Jun 29 '15 at 21:33






  • 1




    What's interesting is that there is something called the S-procedure that does something every similar to this for quadratic forms. That suggests it should be possible for affine forms, but I'll be darned if I can figure out how.
    – Michael Grant
    Jun 30 '15 at 2:04










  • What @aGer is proposing is possible, see my answer to this question.
    – LinAlg
    Jan 14 '17 at 15:04















If you want to show that $P_1 subset P_2$, you have to show that $forall x in P_1 colon A_2 x geq b_2$
– aGer
Jun 29 '15 at 14:21





If you want to show that $P_1 subset P_2$, you have to show that $forall x in P_1 colon A_2 x geq b_2$
– aGer
Jun 29 '15 at 14:21













I wonder if you could do something with minkowski sums and minkowski portal refinement (MPR / Xenocollide) or GJK?
– Alan Wolfe
Jun 29 '15 at 16:39




I wonder if you could do something with minkowski sums and minkowski portal refinement (MPR / Xenocollide) or GJK?
– Alan Wolfe
Jun 29 '15 at 16:39












@aGer I'm trying to do that by coming up with a general method using something like Farkas lemma, but no success so far. :-(
– Tony
Jun 29 '15 at 21:33




@aGer I'm trying to do that by coming up with a general method using something like Farkas lemma, but no success so far. :-(
– Tony
Jun 29 '15 at 21:33




1




1




What's interesting is that there is something called the S-procedure that does something every similar to this for quadratic forms. That suggests it should be possible for affine forms, but I'll be darned if I can figure out how.
– Michael Grant
Jun 30 '15 at 2:04




What's interesting is that there is something called the S-procedure that does something every similar to this for quadratic forms. That suggests it should be possible for affine forms, but I'll be darned if I can figure out how.
– Michael Grant
Jun 30 '15 at 2:04












What @aGer is proposing is possible, see my answer to this question.
– LinAlg
Jan 14 '17 at 15:04




What @aGer is proposing is possible, see my answer to this question.
– LinAlg
Jan 14 '17 at 15:04










3 Answers
3






active

oldest

votes

















up vote
3
down vote



accepted










Well, here's one way to do it. Let $A_i2$ and $b_i2$ denote the $i$th row of $A_2$ and $i$th element of $b_2$, respectively. Then solve $m$ linear programs:
$$beginarrayll
textminimize & A_i2^T x - b_i2 \
textsubject to & A_1 x geq b_1
endarray qquad i=1,2,dots, m$$
If any of these have a negative objective, including possibly $-infty$, then $P_1notsubseteq P_2$. It's not cheap, I grant, but it works.






share|cite|improve this answer




















  • Would the problem be easier if, instead of writing $P_2=x mid A_2 x =b_2, x geq 0 $, I know $P_2$ is a cone with known extreme rays: $P_2= R v mid v geq 0 $?
    – Tony
    Jun 30 '15 at 14:14











  • I don't think so, no. Unfortunately I don't think this is a convex problem. We are fortunate that it can be done this way.
    – Michael Grant
    Jun 30 '15 at 14:17

















up vote
2
down vote













A not so elegant way would be to determine the vertices of $P_1$ and plug them into the constraints for $P_2$, if each vertex satisfies the $P_2$ constraints, then by convexity, so does the entire polyhedron.



As pointed out by @D.W., this approach will typically be very slow, as the number of vertices increases rapidly with the number of edges. Michael Grant's approach, as stated above and accepted, has faster running time.






share|cite|improve this answer






















  • That will work, except that finding the vertices given the faces is not straightforward.
    – Michael Grant
    Jun 30 '15 at 2:01










  • Simplex doesn't attempt enumerate all the vertices, actually... indeed it would be quite bad if it did!
    – Michael Grant
    Jun 30 '15 at 2:48











  • @Tony here's a paper to popular algorithm for vertex enumeration. This general problem is classified as NP-complete, so its not going to come cheap: link.springer.com/article/10.1007%2FBF02293050
    – user237392
    Jun 30 '15 at 4:09






  • 1




    @Bey, well, if we must discuss the prior comments: no, vertex enumeration is not NP-complete. It's not even a NP-problem. NP is a class of decision problems; and NP-complete is a subset of NP. Vertex enumeration is not a decision problem. Moreover, vertex enumeration unconditionally takes exponential time; even if we discover P=NP, vertex enumeration will still take exponential time, as the number of vertices to enumerate can be exponential. The best path forward would be to edit the answer to point out these limitations. Shall I suggest an edit?
    – D.W.
    Aug 26 '16 at 5:32






  • 1




    The more efficient algorithm has already been posted by Michael Grant; its running time is guaranteed to be polynomial if you use the right LP solver, and will typically be efficient in practice. I don't have anything better than that.
    – D.W.
    Aug 26 '16 at 14:41


















up vote
1
down vote













This is equivalent to the feasibility of the following linear constraints:
$$
Lambda A_2 = A_1, Lambda b_2 ge b_1,
$$
where $Lambda$ is a matrix with non-negative entries. The proof follows from the dual of linear programs that Michael mentioned.






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    3 Answers
    3






    active

    oldest

    votes








    3 Answers
    3






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes








    up vote
    3
    down vote



    accepted










    Well, here's one way to do it. Let $A_i2$ and $b_i2$ denote the $i$th row of $A_2$ and $i$th element of $b_2$, respectively. Then solve $m$ linear programs:
    $$beginarrayll
    textminimize & A_i2^T x - b_i2 \
    textsubject to & A_1 x geq b_1
    endarray qquad i=1,2,dots, m$$
    If any of these have a negative objective, including possibly $-infty$, then $P_1notsubseteq P_2$. It's not cheap, I grant, but it works.






    share|cite|improve this answer




















    • Would the problem be easier if, instead of writing $P_2=x mid A_2 x =b_2, x geq 0 $, I know $P_2$ is a cone with known extreme rays: $P_2= R v mid v geq 0 $?
      – Tony
      Jun 30 '15 at 14:14











    • I don't think so, no. Unfortunately I don't think this is a convex problem. We are fortunate that it can be done this way.
      – Michael Grant
      Jun 30 '15 at 14:17














    up vote
    3
    down vote



    accepted










    Well, here's one way to do it. Let $A_i2$ and $b_i2$ denote the $i$th row of $A_2$ and $i$th element of $b_2$, respectively. Then solve $m$ linear programs:
    $$beginarrayll
    textminimize & A_i2^T x - b_i2 \
    textsubject to & A_1 x geq b_1
    endarray qquad i=1,2,dots, m$$
    If any of these have a negative objective, including possibly $-infty$, then $P_1notsubseteq P_2$. It's not cheap, I grant, but it works.






    share|cite|improve this answer




















    • Would the problem be easier if, instead of writing $P_2=x mid A_2 x =b_2, x geq 0 $, I know $P_2$ is a cone with known extreme rays: $P_2= R v mid v geq 0 $?
      – Tony
      Jun 30 '15 at 14:14











    • I don't think so, no. Unfortunately I don't think this is a convex problem. We are fortunate that it can be done this way.
      – Michael Grant
      Jun 30 '15 at 14:17












    up vote
    3
    down vote



    accepted







    up vote
    3
    down vote



    accepted






    Well, here's one way to do it. Let $A_i2$ and $b_i2$ denote the $i$th row of $A_2$ and $i$th element of $b_2$, respectively. Then solve $m$ linear programs:
    $$beginarrayll
    textminimize & A_i2^T x - b_i2 \
    textsubject to & A_1 x geq b_1
    endarray qquad i=1,2,dots, m$$
    If any of these have a negative objective, including possibly $-infty$, then $P_1notsubseteq P_2$. It's not cheap, I grant, but it works.






    share|cite|improve this answer












    Well, here's one way to do it. Let $A_i2$ and $b_i2$ denote the $i$th row of $A_2$ and $i$th element of $b_2$, respectively. Then solve $m$ linear programs:
    $$beginarrayll
    textminimize & A_i2^T x - b_i2 \
    textsubject to & A_1 x geq b_1
    endarray qquad i=1,2,dots, m$$
    If any of these have a negative objective, including possibly $-infty$, then $P_1notsubseteq P_2$. It's not cheap, I grant, but it works.







    share|cite|improve this answer












    share|cite|improve this answer



    share|cite|improve this answer










    answered Jun 30 '15 at 4:02









    Michael Grant

    14.6k11743




    14.6k11743











    • Would the problem be easier if, instead of writing $P_2=x mid A_2 x =b_2, x geq 0 $, I know $P_2$ is a cone with known extreme rays: $P_2= R v mid v geq 0 $?
      – Tony
      Jun 30 '15 at 14:14











    • I don't think so, no. Unfortunately I don't think this is a convex problem. We are fortunate that it can be done this way.
      – Michael Grant
      Jun 30 '15 at 14:17
















    • Would the problem be easier if, instead of writing $P_2=x mid A_2 x =b_2, x geq 0 $, I know $P_2$ is a cone with known extreme rays: $P_2= R v mid v geq 0 $?
      – Tony
      Jun 30 '15 at 14:14











    • I don't think so, no. Unfortunately I don't think this is a convex problem. We are fortunate that it can be done this way.
      – Michael Grant
      Jun 30 '15 at 14:17















    Would the problem be easier if, instead of writing $P_2=x mid A_2 x =b_2, x geq 0 $, I know $P_2$ is a cone with known extreme rays: $P_2= R v mid v geq 0 $?
    – Tony
    Jun 30 '15 at 14:14





    Would the problem be easier if, instead of writing $P_2=x mid A_2 x =b_2, x geq 0 $, I know $P_2$ is a cone with known extreme rays: $P_2= R v mid v geq 0 $?
    – Tony
    Jun 30 '15 at 14:14













    I don't think so, no. Unfortunately I don't think this is a convex problem. We are fortunate that it can be done this way.
    – Michael Grant
    Jun 30 '15 at 14:17




    I don't think so, no. Unfortunately I don't think this is a convex problem. We are fortunate that it can be done this way.
    – Michael Grant
    Jun 30 '15 at 14:17










    up vote
    2
    down vote













    A not so elegant way would be to determine the vertices of $P_1$ and plug them into the constraints for $P_2$, if each vertex satisfies the $P_2$ constraints, then by convexity, so does the entire polyhedron.



    As pointed out by @D.W., this approach will typically be very slow, as the number of vertices increases rapidly with the number of edges. Michael Grant's approach, as stated above and accepted, has faster running time.






    share|cite|improve this answer






















    • That will work, except that finding the vertices given the faces is not straightforward.
      – Michael Grant
      Jun 30 '15 at 2:01










    • Simplex doesn't attempt enumerate all the vertices, actually... indeed it would be quite bad if it did!
      – Michael Grant
      Jun 30 '15 at 2:48











    • @Tony here's a paper to popular algorithm for vertex enumeration. This general problem is classified as NP-complete, so its not going to come cheap: link.springer.com/article/10.1007%2FBF02293050
      – user237392
      Jun 30 '15 at 4:09






    • 1




      @Bey, well, if we must discuss the prior comments: no, vertex enumeration is not NP-complete. It's not even a NP-problem. NP is a class of decision problems; and NP-complete is a subset of NP. Vertex enumeration is not a decision problem. Moreover, vertex enumeration unconditionally takes exponential time; even if we discover P=NP, vertex enumeration will still take exponential time, as the number of vertices to enumerate can be exponential. The best path forward would be to edit the answer to point out these limitations. Shall I suggest an edit?
      – D.W.
      Aug 26 '16 at 5:32






    • 1




      The more efficient algorithm has already been posted by Michael Grant; its running time is guaranteed to be polynomial if you use the right LP solver, and will typically be efficient in practice. I don't have anything better than that.
      – D.W.
      Aug 26 '16 at 14:41















    up vote
    2
    down vote













    A not so elegant way would be to determine the vertices of $P_1$ and plug them into the constraints for $P_2$, if each vertex satisfies the $P_2$ constraints, then by convexity, so does the entire polyhedron.



    As pointed out by @D.W., this approach will typically be very slow, as the number of vertices increases rapidly with the number of edges. Michael Grant's approach, as stated above and accepted, has faster running time.






    share|cite|improve this answer






















    • That will work, except that finding the vertices given the faces is not straightforward.
      – Michael Grant
      Jun 30 '15 at 2:01










    • Simplex doesn't attempt enumerate all the vertices, actually... indeed it would be quite bad if it did!
      – Michael Grant
      Jun 30 '15 at 2:48











    • @Tony here's a paper to popular algorithm for vertex enumeration. This general problem is classified as NP-complete, so its not going to come cheap: link.springer.com/article/10.1007%2FBF02293050
      – user237392
      Jun 30 '15 at 4:09






    • 1




      @Bey, well, if we must discuss the prior comments: no, vertex enumeration is not NP-complete. It's not even a NP-problem. NP is a class of decision problems; and NP-complete is a subset of NP. Vertex enumeration is not a decision problem. Moreover, vertex enumeration unconditionally takes exponential time; even if we discover P=NP, vertex enumeration will still take exponential time, as the number of vertices to enumerate can be exponential. The best path forward would be to edit the answer to point out these limitations. Shall I suggest an edit?
      – D.W.
      Aug 26 '16 at 5:32






    • 1




      The more efficient algorithm has already been posted by Michael Grant; its running time is guaranteed to be polynomial if you use the right LP solver, and will typically be efficient in practice. I don't have anything better than that.
      – D.W.
      Aug 26 '16 at 14:41













    up vote
    2
    down vote










    up vote
    2
    down vote









    A not so elegant way would be to determine the vertices of $P_1$ and plug them into the constraints for $P_2$, if each vertex satisfies the $P_2$ constraints, then by convexity, so does the entire polyhedron.



    As pointed out by @D.W., this approach will typically be very slow, as the number of vertices increases rapidly with the number of edges. Michael Grant's approach, as stated above and accepted, has faster running time.






    share|cite|improve this answer














    A not so elegant way would be to determine the vertices of $P_1$ and plug them into the constraints for $P_2$, if each vertex satisfies the $P_2$ constraints, then by convexity, so does the entire polyhedron.



    As pointed out by @D.W., this approach will typically be very slow, as the number of vertices increases rapidly with the number of edges. Michael Grant's approach, as stated above and accepted, has faster running time.







    share|cite|improve this answer














    share|cite|improve this answer



    share|cite|improve this answer








    edited Aug 26 '16 at 16:53

























    answered Jun 29 '15 at 16:29







    user237392


















    • That will work, except that finding the vertices given the faces is not straightforward.
      – Michael Grant
      Jun 30 '15 at 2:01










    • Simplex doesn't attempt enumerate all the vertices, actually... indeed it would be quite bad if it did!
      – Michael Grant
      Jun 30 '15 at 2:48











    • @Tony here's a paper to popular algorithm for vertex enumeration. This general problem is classified as NP-complete, so its not going to come cheap: link.springer.com/article/10.1007%2FBF02293050
      – user237392
      Jun 30 '15 at 4:09






    • 1




      @Bey, well, if we must discuss the prior comments: no, vertex enumeration is not NP-complete. It's not even a NP-problem. NP is a class of decision problems; and NP-complete is a subset of NP. Vertex enumeration is not a decision problem. Moreover, vertex enumeration unconditionally takes exponential time; even if we discover P=NP, vertex enumeration will still take exponential time, as the number of vertices to enumerate can be exponential. The best path forward would be to edit the answer to point out these limitations. Shall I suggest an edit?
      – D.W.
      Aug 26 '16 at 5:32






    • 1




      The more efficient algorithm has already been posted by Michael Grant; its running time is guaranteed to be polynomial if you use the right LP solver, and will typically be efficient in practice. I don't have anything better than that.
      – D.W.
      Aug 26 '16 at 14:41

















    • That will work, except that finding the vertices given the faces is not straightforward.
      – Michael Grant
      Jun 30 '15 at 2:01










    • Simplex doesn't attempt enumerate all the vertices, actually... indeed it would be quite bad if it did!
      – Michael Grant
      Jun 30 '15 at 2:48











    • @Tony here's a paper to popular algorithm for vertex enumeration. This general problem is classified as NP-complete, so its not going to come cheap: link.springer.com/article/10.1007%2FBF02293050
      – user237392
      Jun 30 '15 at 4:09






    • 1




      @Bey, well, if we must discuss the prior comments: no, vertex enumeration is not NP-complete. It's not even a NP-problem. NP is a class of decision problems; and NP-complete is a subset of NP. Vertex enumeration is not a decision problem. Moreover, vertex enumeration unconditionally takes exponential time; even if we discover P=NP, vertex enumeration will still take exponential time, as the number of vertices to enumerate can be exponential. The best path forward would be to edit the answer to point out these limitations. Shall I suggest an edit?
      – D.W.
      Aug 26 '16 at 5:32






    • 1




      The more efficient algorithm has already been posted by Michael Grant; its running time is guaranteed to be polynomial if you use the right LP solver, and will typically be efficient in practice. I don't have anything better than that.
      – D.W.
      Aug 26 '16 at 14:41
















    That will work, except that finding the vertices given the faces is not straightforward.
    – Michael Grant
    Jun 30 '15 at 2:01




    That will work, except that finding the vertices given the faces is not straightforward.
    – Michael Grant
    Jun 30 '15 at 2:01












    Simplex doesn't attempt enumerate all the vertices, actually... indeed it would be quite bad if it did!
    – Michael Grant
    Jun 30 '15 at 2:48





    Simplex doesn't attempt enumerate all the vertices, actually... indeed it would be quite bad if it did!
    – Michael Grant
    Jun 30 '15 at 2:48













    @Tony here's a paper to popular algorithm for vertex enumeration. This general problem is classified as NP-complete, so its not going to come cheap: link.springer.com/article/10.1007%2FBF02293050
    – user237392
    Jun 30 '15 at 4:09




    @Tony here's a paper to popular algorithm for vertex enumeration. This general problem is classified as NP-complete, so its not going to come cheap: link.springer.com/article/10.1007%2FBF02293050
    – user237392
    Jun 30 '15 at 4:09




    1




    1




    @Bey, well, if we must discuss the prior comments: no, vertex enumeration is not NP-complete. It's not even a NP-problem. NP is a class of decision problems; and NP-complete is a subset of NP. Vertex enumeration is not a decision problem. Moreover, vertex enumeration unconditionally takes exponential time; even if we discover P=NP, vertex enumeration will still take exponential time, as the number of vertices to enumerate can be exponential. The best path forward would be to edit the answer to point out these limitations. Shall I suggest an edit?
    – D.W.
    Aug 26 '16 at 5:32




    @Bey, well, if we must discuss the prior comments: no, vertex enumeration is not NP-complete. It's not even a NP-problem. NP is a class of decision problems; and NP-complete is a subset of NP. Vertex enumeration is not a decision problem. Moreover, vertex enumeration unconditionally takes exponential time; even if we discover P=NP, vertex enumeration will still take exponential time, as the number of vertices to enumerate can be exponential. The best path forward would be to edit the answer to point out these limitations. Shall I suggest an edit?
    – D.W.
    Aug 26 '16 at 5:32




    1




    1




    The more efficient algorithm has already been posted by Michael Grant; its running time is guaranteed to be polynomial if you use the right LP solver, and will typically be efficient in practice. I don't have anything better than that.
    – D.W.
    Aug 26 '16 at 14:41





    The more efficient algorithm has already been posted by Michael Grant; its running time is guaranteed to be polynomial if you use the right LP solver, and will typically be efficient in practice. I don't have anything better than that.
    – D.W.
    Aug 26 '16 at 14:41











    up vote
    1
    down vote













    This is equivalent to the feasibility of the following linear constraints:
    $$
    Lambda A_2 = A_1, Lambda b_2 ge b_1,
    $$
    where $Lambda$ is a matrix with non-negative entries. The proof follows from the dual of linear programs that Michael mentioned.






    share|cite|improve this answer
























      up vote
      1
      down vote













      This is equivalent to the feasibility of the following linear constraints:
      $$
      Lambda A_2 = A_1, Lambda b_2 ge b_1,
      $$
      where $Lambda$ is a matrix with non-negative entries. The proof follows from the dual of linear programs that Michael mentioned.






      share|cite|improve this answer






















        up vote
        1
        down vote










        up vote
        1
        down vote









        This is equivalent to the feasibility of the following linear constraints:
        $$
        Lambda A_2 = A_1, Lambda b_2 ge b_1,
        $$
        where $Lambda$ is a matrix with non-negative entries. The proof follows from the dual of linear programs that Michael mentioned.






        share|cite|improve this answer












        This is equivalent to the feasibility of the following linear constraints:
        $$
        Lambda A_2 = A_1, Lambda b_2 ge b_1,
        $$
        where $Lambda$ is a matrix with non-negative entries. The proof follows from the dual of linear programs that Michael mentioned.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Aug 23 at 2:36









        sadra

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