# In mathematical essays, is "at x=a", "for x=a", "when x=a", "if x=a", or even "with x=a", a better choice? [closed]

Which one of the following sentences sounds better to a native ear?

1. At \$x=a\$, \$f(x,t)\$ is an even function of \$t\$.
2. For \$x=a\$, \$f(x,t)\$ is an even function of \$t\$.
3. When \$x=a\$, \$f(x,t)\$ is an even function of \$t\$.
4. If \$x=a\$, (then) \$f(x,t)\$ is an even function of \$t\$.
5. With \$x=a\$, \$f(x,t)\$ is an even function of \$t\$.
6. Given (that) \$x=a\$, \$f(x,t)\$ is an even function of \$t\$.
7. Provided (that) \$x=a\$, \$f(x,t)\$ is an even function of \$t\$.
• I’m voting to close this question because this would be a better fit on a Mathematics or English SE site. Feb 2 at 14:18
• This seems to be a question about the basic conventions of writing within your research field. You should have the idea of what the standard is from all the papers you've read so far. If still unsure how to chose between the standards, talk to your advisor. Feb 2 at 14:58
• If a value for a has already been specified, I'd probably write "f(a,t) is an even function of t." Feb 3 at 0:37