Let  $A$ be a central, simple algebra of degree $2n$ with orthogonal involution $\sigma$.

Let SB$(A)$ the Severi-Brauer variety, which is the variety of left ideals of reduced dimension ***one*** in $A$.

The involution variety Inv$(A,\sigma)= \{ I \in $SB$(A)$ $|$ $\sigma(I)I = 0\}$ is known to be a hyperplane section of SB$(A)$.

We define a generalized SB$(A)_{l,n}$ as the variety of left ideals in $A$ of reduced dimension $l$, when $deg(A) = n$. In an analogue way one can define a generalized involution variety Inv$(A,\sigma)_{l,n}$.

I asked myself, if for $l$ other than $1$, Inv$(A,\sigma)_{l,n}$ is a hyperplane section of SB$(A)_{l,n}$. However calculatiing the dimensions i think i found that this is *not* possible. However we still can ask

**Question:** For central, simple algebras $A,B$ of degrees $n,2m$, and for $\sigma$ beeing an orthogonal involution on $B$. Can there be $l,k$ such that
 Inv$(B,\sigma)_{k,2m}$ is a hyperplane section of SB$(A)_{l,n}$ ?

What inspired me to think about such things is a result from 

D. Krashen - Zero cycles on homogeneous varieties,

stating that for $A$ of degree $4$ and $B$ of degree $6$ there is an *isomorphism* between 
 Inv$(B,\sigma)_{1,6}$ and SB$(A)_{2,4}$.