3 votes 3 votes What are the chromatic number of following graphs? Answer is 6 and 4 respectively.But i am getting 3 for both. Please someone confirm this? Graph Theory graph-theory discrete-mathematics graph-connectivity graph-coloring + – rahul sharma 5 asked Jun 12, 2017 recategorized Oct 9, 2023 by Hira Thakur rahul sharma 5 1.9k views answer comment Share Follow See 1 comment See all 1 1 comment reply Abbas commented Mar 17, 2018 reply Follow Share The answer which you are getting is for EDGE CHROMATIC number NOT (vertex) CHROMATIC number.. 1 votes 1 votes Please log in or register to add a comment.
Best answer 12 votes 12 votes Yes we can color both of them with 3 color so that no two same color is adjacent. but how can we sure that it is not less than 3. As both the graph consist triangle it can't be color with less than 3. So we at least require 3 color to color them. Moreover they are planer graph, according to four color theorem : The chromatic number of a planar graph is no greater than four. https://en.wikipedia.org/wiki/Four_color_theorem Hemant Parihar answered Jun 13, 2017 selected Jun 13, 2017 by mcjoshi Hemant Parihar comment Share Follow See all 0 reply Please log in or register to add a comment.
2 votes 2 votes yes both of them have 3 chromatic number pawan kumarln answered Jun 13, 2017 pawan kumarln comment Share Follow See all 0 reply Please log in or register to add a comment.
–2 votes –2 votes 3 is the correct answer for both abhishek tiwary answered Jun 21, 2017 abhishek tiwary comment Share Follow See all 0 reply Please log in or register to add a comment.