Two roads to the null energy condition

Mathematics

• Null 84%
• Energy 62%
• Gravity 50%
• Second Law of Thermodynamics 33%
• Sweeping 31%
• General Relativity 28%
• String Theory 28%
• Einstein Equations 28%
• Thermodynamics 24%
• Two Dimensions 20%
• Entropy 18%
• Formulation 14%

Physics & Astronomy

• roads 100%
• gravitation 34%
• thermodynamics 31%
• energy 27%
• Einstein equations 26%
• string theory 24%
• relativity 21%
• entropy 17%
• formulations 16%

Earth & Environmental Sciences

• road 66%
• thermodynamics 48%
• gravity 45%
• energy 45%
• entropy 27%