Osiris Xu questions

• How to check whether an infinite set is closed under addition with a computer code?
• Any efficient easy way to find the maximum list among N lists with the same length using Mathematica?
• How to compile a program to make it capable to use >4GB memory on 32-bit Linux?
• What is the fastest way to autobreak a line of gigabytes separated by keywords using bash shell?
• How to do such substitutions with AWK or sed or Perl?
• How to remove the Null symbol in a Table in Mathematica?
• Is there any efficient easy way to compare two lists with the same length with Mathematica?

Osiris Xu answers