Update 2024-18-12 (PST): - "Losing to someone who has been world champion before" refers to losing the world championship title to a person who has previously been world champion (AI summary of creator comment)
All "lose to" or "be defeated by" etc refer to the competition for the championship itself. Similarly, Defend refers to defending the championship. Also note that unless otherwise specified, statements such as "will defend his title 3 times" refer to his current holding of the title. For example, say he defends well in 2025 and 2026, then loses in 2027, then wins it again in 2028, then defends it again for the 3rd time in 2029. That would NOT count as defending 3 times. That claim would have been NO as soon as he didn't successfully defend it 3 times in a row from now.
Similarly "lose the championship title to someone who..." refers to THIS instance of him being champion.
@Scipio11 will clarify, thanks. In general, I believe in this market that "losing to ..." refers to "losing the title to a person who ..."
"Will have won by his opponent resigning or quitting or other irregular outing at least one game" resolves True -- e.g., the last game was won by Ding resigning: https://en.wikipedia.org/wiki/World_Chess_Championship_2024