Is Conjugate Symmetry Enough for a Hermitian Inner Product?

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SUMMARY

The discussion centers on the properties of Hermitian inner products, specifically the relationship between conjugate symmetry and antilinearity. It is established that an inner product is Hermitian if it satisfies conjugate symmetry and is antilinear in the second slot. The confusion arises from the assumption that conjugate symmetry implies antilinearity in both slots, which is incorrect. A proof is requested to clarify this misunderstanding, emphasizing the distinction between linearity in the first slot and antilinearity in the second.

PREREQUISITES
  • Understanding of inner product spaces
  • Familiarity with the concept of conjugate symmetry
  • Knowledge of linearity and antilinearity in mathematical contexts
  • Basic proficiency in complex numbers and their properties
NEXT STEPS
  • Study the definition and properties of Hermitian inner products in detail
  • Explore proofs related to conjugate symmetry and antilinearity
  • Investigate examples of inner products in complex vector spaces
  • Learn about the implications of linearity and antilinearity in functional analysis
USEFUL FOR

Mathematicians, students of linear algebra, and anyone studying functional analysis will benefit from this discussion, particularly those interested in the properties of inner products and their applications in complex vector spaces.

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I'm getting some confusing information from different sources. If an inner product satisfies conjugate symmetry, it is called Hermitian. But the definition of a hermitian inner product says it must be antilinear in the second slot only. Doesn't conjugate symmetry imply that it's antilinear in both slots?
 
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Conjugate symmetry (plus linearity in the first slot) implies antilinearity in the second:

\langle u,\,\alpha v\rangle = \overline{\langle \alpha v,\, u\rangle } = \overline{\alpha \langle v,\, u\rangle } = \overline{\alpha}\overline{\langle v,\, u\rangle } = \overline{\alpha}\langle u,\, v\rangle

If you think conjugate symmetry implies antilinearity in both, present a proof for it.
 
I thought conjugate symmetry and antilinearity in the second slot implied antilinearity in the first, but I made an error when pulling out the constant.
 

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