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YCor
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For every group every group $G$, the reducedreduced group $C^* $ algebra $C^*_{red} G$ is$C^*$-algebra $C^*_{red}G$ is equipped with the inner product $<a,b>=tr(ab^*)$ wherherproduct $"tr"$$\langle a,b\rangle=tr(ab^*)$ where "$tr$" is thethe standard tracetrace on groupgroup $C^*$ algebras-algebras.

For what kindwhat kind of groups $G$, $C^*_{red}G$ admit a boundedbounded skew symmetric-symmetric $2-$$2$-linear map $\wedge: C^*_{red}G\times C^*_{red}G \to C^*_{red} G$map $\wedge: C^*_{red}G\times C^*_{red}G \to C^*_{red}G$ with the following properties:

  1. For every $a,b \in C^*_{red}G,\; a\wedge b$ is$a,b \in C^*_{red}G$, $a\wedge b$ is perpendicular to bothboth $a,b$.

2)For everyevery two independent elements $a,b\in C^*_{red} G, a\wedge b$ is$a,b\in C^*_{red} G$, $a\wedge b$ is a non zero nonzero element?

our questionOur question is inspired by the following paperinspired by the following paper:

https://pdfs.semanticscholar.org/1f6b/ff1e992f60eb87b35c3ceed04272fb5cc298.pdf W. S. Massey, Cross Products of Vectors in Higher Dimensional Euclidean Spaces. The American Mathematical Monthly, Vol. 90, No. 10 (Dec., 1983), pp. 697-701.

For every group $G$, the reduced group $C^* $ algebra $C^*_{red} G$ is equipped with the inner product $<a,b>=tr(ab^*)$ wherher $"tr"$ is the standard trace on group $C^*$ algebras.

For what kind of groups $G$, $C^*_{red}G$ admit a bounded skew symmetric $2-$linear map $\wedge: C^*_{red}G\times C^*_{red}G \to C^*_{red} G$ with the following properties:

  1. For every $a,b \in C^*_{red}G,\; a\wedge b$ is perpendicular to both $a,b$

2)For every two independent elements $a,b\in C^*_{red} G, a\wedge b$ is a non zero element?

our question is inspired by the following paper:

https://pdfs.semanticscholar.org/1f6b/ff1e992f60eb87b35c3ceed04272fb5cc298.pdf

For every group $G$, the reduced group $C^*$-algebra $C^*_{red}G$ is equipped with the inner product $\langle a,b\rangle=tr(ab^*)$ where "$tr$" is the standard trace on group $C^*$-algebras.

For what kind of groups $G$, $C^*_{red}G$ admit a bounded skew-symmetric $2$-linear map $\wedge: C^*_{red}G\times C^*_{red}G \to C^*_{red}G$ with the following properties:

  1. For every $a,b \in C^*_{red}G$, $a\wedge b$ is perpendicular to both $a,b$.

2)For every two independent elements $a,b\in C^*_{red} G$, $a\wedge b$ is a nonzero element?

Our question is inspired by the following paper:

W. S. Massey, Cross Products of Vectors in Higher Dimensional Euclidean Spaces. The American Mathematical Monthly, Vol. 90, No. 10 (Dec., 1983), pp. 697-701.

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Ali Taghavi
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A cross product on $C^*_{red} G$

For every group $G$, the reduced group $C^* $ algebra $C^*_{red} G$ is equipped with the inner product $<a,b>=tr(ab^*)$ wherher $"tr"$ is the standard trace on group $C^*$ algebras.

For what kind of groups $G$, $C^*_{red}G$ admit a bounded skew symmetric $2-$linear map $\wedge: C^*_{red}G\times C^*_{red}G \to C^*_{red} G$ with the following properties:

  1. For every $a,b \in C^*_{red}G,\; a\wedge b$ is perpendicular to both $a,b$

2)For every two independent elements $a,b\in C^*_{red} G, a\wedge b$ is a non zero element?

our question is inspired by the following paper:

https://pdfs.semanticscholar.org/1f6b/ff1e992f60eb87b35c3ceed04272fb5cc298.pdf