On Bridge Graphs with Local Antimagic Chromatic Number 3

Let <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mo>=</mo><mo>(</mo><mi>V</mi><mo>,</mo><mi>E</mi><mo>)</mo>...

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Main Authors: Wai-Chee Shiu, Gee-Choon Lau, Ruixue Zhang
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Mathematics
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Online Access:https://www.mdpi.com/2227-7390/13/1/16
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author Wai-Chee Shiu
Gee-Choon Lau
Ruixue Zhang
author_facet Wai-Chee Shiu
Gee-Choon Lau
Ruixue Zhang
author_sort Wai-Chee Shiu
collection DOAJ
description Let <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mo>=</mo><mo>(</mo><mi>V</mi><mo>,</mo><mi>E</mi><mo>)</mo></mrow></semantics></math></inline-formula> be a connected graph. A bijection <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>f</mi><mo>:</mo><mi>E</mi><mo>→</mo><mo>{</mo><mn>1</mn><mo>,</mo><mo>…</mo><mo>,</mo><mo>|</mo><mi>E</mi><mo>|</mo><mo>}</mo></mrow></semantics></math></inline-formula> is called a local antimagic labeling if, for any two adjacent vertices <i>x</i> and <i>y</i>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mi>f</mi><mo>+</mo></msup><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow><mo>≠</mo><msup><mi>f</mi><mo>+</mo></msup><mrow><mo>(</mo><mi>y</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula>, where <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mi>f</mi><mo>+</mo></msup><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow><mo>=</mo><msub><mo>∑</mo><mrow><mi>e</mi><mo>∈</mo><mi>E</mi><mo>(</mo><mi>x</mi><mo>)</mo></mrow></msub><mi>f</mi><mrow><mo>(</mo><mi>e</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula>, and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>E</mi><mo>(</mo><mi>x</mi><mo>)</mo></mrow></semantics></math></inline-formula> is the set of edges incident to <i>x</i>. Thus, a local antimagic labeling induces a proper vertex coloring of <i>G</i>, where the vertex <i>x</i> is assigned the color <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mi>f</mi><mo>+</mo></msup><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula>. The local antimagic chromatic number <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>χ</mi><mrow><mi>l</mi><mi>a</mi></mrow></msub><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula> is the minimum number of colors taken over all colorings induced by local antimagic labelings of <i>G</i>. In this paper, we present some families of bridge graphs with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>χ</mi><mrow><mi>l</mi><mi>a</mi></mrow></msub><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow><mo>=</mo><mn>3</mn></mrow></semantics></math></inline-formula> and give several ways to construct bridge graphs with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>χ</mi><mrow><mi>l</mi><mi>a</mi></mrow></msub><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow><mo>=</mo><mn>3</mn></mrow></semantics></math></inline-formula>.
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spelling doaj-art-5d3676c61fb849159d88a32aab755fca2025-01-10T13:17:58ZengMDPI AGMathematics2227-73902024-12-011311610.3390/math13010016On Bridge Graphs with Local Antimagic Chromatic Number 3Wai-Chee Shiu0Gee-Choon Lau1Ruixue Zhang2Department of Mathematics, The Chinese University of Hong Kong, Shatin, Hong KongCollege of Computing, Informatics and Mathematics, Universiti Teknologi MARA, Johor Branch, Segamat Campus, Johor 85000, MalaysiaSchool of Mathematics and Statistics, Qingdao University, Qingdao 266071, ChinaLet <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mo>=</mo><mo>(</mo><mi>V</mi><mo>,</mo><mi>E</mi><mo>)</mo></mrow></semantics></math></inline-formula> be a connected graph. A bijection <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>f</mi><mo>:</mo><mi>E</mi><mo>→</mo><mo>{</mo><mn>1</mn><mo>,</mo><mo>…</mo><mo>,</mo><mo>|</mo><mi>E</mi><mo>|</mo><mo>}</mo></mrow></semantics></math></inline-formula> is called a local antimagic labeling if, for any two adjacent vertices <i>x</i> and <i>y</i>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mi>f</mi><mo>+</mo></msup><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow><mo>≠</mo><msup><mi>f</mi><mo>+</mo></msup><mrow><mo>(</mo><mi>y</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula>, where <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mi>f</mi><mo>+</mo></msup><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow><mo>=</mo><msub><mo>∑</mo><mrow><mi>e</mi><mo>∈</mo><mi>E</mi><mo>(</mo><mi>x</mi><mo>)</mo></mrow></msub><mi>f</mi><mrow><mo>(</mo><mi>e</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula>, and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>E</mi><mo>(</mo><mi>x</mi><mo>)</mo></mrow></semantics></math></inline-formula> is the set of edges incident to <i>x</i>. Thus, a local antimagic labeling induces a proper vertex coloring of <i>G</i>, where the vertex <i>x</i> is assigned the color <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mi>f</mi><mo>+</mo></msup><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula>. The local antimagic chromatic number <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>χ</mi><mrow><mi>l</mi><mi>a</mi></mrow></msub><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula> is the minimum number of colors taken over all colorings induced by local antimagic labelings of <i>G</i>. In this paper, we present some families of bridge graphs with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>χ</mi><mrow><mi>l</mi><mi>a</mi></mrow></msub><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow><mo>=</mo><mn>3</mn></mrow></semantics></math></inline-formula> and give several ways to construct bridge graphs with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>χ</mi><mrow><mi>l</mi><mi>a</mi></mrow></msub><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow><mo>=</mo><mn>3</mn></mrow></semantics></math></inline-formula>.https://www.mdpi.com/2227-7390/13/1/16local antimagic labelinglocal antimagic chromatic number<i>s</i>-bridge graphs
spellingShingle Wai-Chee Shiu
Gee-Choon Lau
Ruixue Zhang
On Bridge Graphs with Local Antimagic Chromatic Number 3
Mathematics
local antimagic labeling
local antimagic chromatic number
<i>s</i>-bridge graphs
title On Bridge Graphs with Local Antimagic Chromatic Number 3
title_full On Bridge Graphs with Local Antimagic Chromatic Number 3
title_fullStr On Bridge Graphs with Local Antimagic Chromatic Number 3
title_full_unstemmed On Bridge Graphs with Local Antimagic Chromatic Number 3
title_short On Bridge Graphs with Local Antimagic Chromatic Number 3
title_sort on bridge graphs with local antimagic chromatic number 3
topic local antimagic labeling
local antimagic chromatic number
<i>s</i>-bridge graphs
url https://www.mdpi.com/2227-7390/13/1/16
work_keys_str_mv AT waicheeshiu onbridgegraphswithlocalantimagicchromaticnumber3
AT geechoonlau onbridgegraphswithlocalantimagicchromaticnumber3
AT ruixuezhang onbridgegraphswithlocalantimagicchromaticnumber3