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I was browsing Stack Overflow, and I came across this question, asked by a user claiming to be under the age of 13, in this case, 7 years old. As far as I know, children under the age of 13 are not allowed to sign up for an account, but upon further investigation, I discovered that the following ...
After a clarifying discussion I see that my downvote was not necessary.
Do I have to wait until the post is edited and then upvote or is there another possibility?
Alice and Bob are two commonly used placeholder names. They are used for archetypal characters in fields such as cryptography, game theory and physics. The names are used for convenience; for example, "Alice sends a message to Bob encrypted with his public key" is easier to follow than "Party A sends a message to Party B encrypted by Party B's public key." Following the alphabet, the specific names have evolved into common parlance within these fields—helping technical topics to be explained in a more understandable fashion.
== OverviewEdit ==
These placeholder names are used for convenience and...
The statement is better in the following form:
The Principle of Equivalence implies that there exists a coordinate system such that the metric of spacetime is locally $\eta_{\mu\nu}$.
Note the word locally. If there is real curvature, then there exists no coordinate system $x$ such that $g_...
