Description

A 1324-avoiding (0,1)-matrix is an π‘šΓ—π‘› matrix that does not contain the 1324-pattern. Our goal is to find the maximum number of 1’s that an π‘š Γ— 𝑛 1324-avoiding (0,1)-matrix can contain. We build upon Brualdi and Cao’s recent work, where they characterized the π‘š Γ— 𝑛 1234-avoiding matrices with the maximum number of 1’s. They found that these matrices can contain up to 3(π‘š + 𝑛 βˆ’ 3) 1’s. We originally conjectured that 1324-avoiding matrices must contain at most the same number of 1’s, as is the case with the six patterns formed by permutations of {1,2,3}. However, we have found 1324-avoiding matrices that contain more 1’s than those that are 1234-avoiding, and we provide a conjecture for the maximum number of 1’s that a 1324-avoiding matrix can contain.

Presenter Bio

Speaker: Megan Bennett

Department of Mathematics Halmos College of Arts and Sciences

Faculty Mentor: Dr. Lei Cao

Department of Mathematics Halmos College of Arts and Sciences

Date of Event

Tuesday, November 28, 2023

Location

Parker Room 301

Included in

Mathematics Commons

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Nov 28th, 12:30 PM Nov 28th, 1:15 PM

1324-Avoiding (0,1)-Matrices

Parker Room 301

A 1324-avoiding (0,1)-matrix is an π‘šΓ—π‘› matrix that does not contain the 1324-pattern. Our goal is to find the maximum number of 1’s that an π‘š Γ— 𝑛 1324-avoiding (0,1)-matrix can contain. We build upon Brualdi and Cao’s recent work, where they characterized the π‘š Γ— 𝑛 1234-avoiding matrices with the maximum number of 1’s. They found that these matrices can contain up to 3(π‘š + 𝑛 βˆ’ 3) 1’s. We originally conjectured that 1324-avoiding matrices must contain at most the same number of 1’s, as is the case with the six patterns formed by permutations of {1,2,3}. However, we have found 1324-avoiding matrices that contain more 1’s than those that are 1234-avoiding, and we provide a conjecture for the maximum number of 1’s that a 1324-avoiding matrix can contain.