I saw an equation as the following one. enter image description here

  • What is the meaning of the symbol looking like an inverse T?
  • How about the symbol "^"?


The following is the context: enter image description here enter image description here

This is the source:

On Updating Problems in Latent Semantic Indexing, SIAM Journal on Scientific Computing - 21(2):pp. 782-791;

  • 3
    $\begingroup$ It might mean orthogonal complement, depending on what kind of an object $U_k$ is. $\endgroup$ – goblin Oct 25 '14 at 11:39
  • $\begingroup$ Thanks. I think you are right. Orthogonal complement is a new concept to me. $\endgroup$ – Tyler 十三将士归玉门 Oct 25 '14 at 12:17
  • $\begingroup$ How about the symbol "^"? $\endgroup$ – Tyler 十三将士归玉门 Oct 25 '14 at 12:23
  • 1
    $\begingroup$ The "^" symbol is not universally defined. You'll have to reference the text to see exactly what it is. It may be that they wanted to call the matrix something different so rather than calling it "P" they called it "P hat". $\endgroup$ – NicNic8 Oct 25 '14 at 16:18
  • $\begingroup$ I agree with @NicNic8, I think "P hat" is just meant to be treated as its own symbol, in much the same way as $x'$ is sometimes used as a symbol distinct from $x$. $\endgroup$ – goblin Oct 26 '14 at 13:24

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.