Fronts and lexicographically well-orderer

HyacinthH

New member
Joined
Sep 1, 2021
Messages
2
Hi everyone!

I have a problem with these lemmas(II.2.18 and II.2.22, front from Nash-William theory). I know it is probably simple, but my brain can't find any good solution to prove it. I got a headache from it haha . Can please someone explains it to me? Thanks for all answers! I tried to do something with it, but nothing with i can share, because I get totally nothing :(
pytania.PNG
 
Hi everyone!

I have a problem with these lemmas(II.2.18 and II.2.22, front from Nash-William theory). I know it is probably simple, but my brain can't find any good solution to prove it. I got a headache from it haha . Can please someone explains it to me? Thanks for all answers! I tried to do something with it, but nothing with i can share, because I get totally nothing :(
View attachment 28735


Please define for us, from your textbook or class-notes or Google:

  • Fronts on the domain
  • lexicographical rank

1630531384005.png
 
Thanks, for the answer. I will send definition of front, but in my textbook there is nothing about lexicographical rank. It says only that "Every front is lexicographically well-ordered" nothing more. This square subset means that s is an initial segment of t.
front.PNG
 
Top