Definable relations in finite dimensional subspace lattices with involution. Part II: Quantifier free and homogeneous descriptions


Abstract in English

For finite dimensional hermitean inner product spaces $V$, over $*$-fields $F$, and in the presence of orthogonal bases providing form elements in the prime subfield of $F$, we show that quantifier free definable relations in the subspace lattice $L(V)$ with involution by taking orthogonals, admit quantifier free descriptions within $F$, also in terms of Grassmann-Plucker coordinates.In the latter setting, homogeneous descriptions are obtained if one allows quantification type $Sigma_1$. In absence of involution, these results remain valid.

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