A disc-shaped plate with a holder, which form a system "plate-holder", wherein the plate has a surface that is circular over large sections of its circumference with an outer plate edge, and the material of the plate has a first thermal expansion coefficient α1, and the holder has an opening that is circular over large sections of its circumference and is delimited by an inner holder edge, and the material of the holder has a second thermal expansion coefficient a2, characterized in that, - at room temperature, the circumference of the opening of the holder is greater than the circumference of the surface of the plate, whereby, when the plate is positioned centrally in the opening of the holder, a gap with a defined gap width S between the plate edge and the inner holder edge is provided, and - α2<α1, and - the plate edge has one or more protrusions, which, viewed from the center point of the circular surface, extend over protrusion lengths in a radial direction starting from the surface of the plate edge and reach into corresponding recesses with recess lengths of the holder edge, and/or the plate edge has one or more recesses, which, viewed from the plate edge, extend over recess lengths toward the center point of the circular surface, and corresponding protrusions of the holder edge with protrusion lengths reach into them, - wherein the system "plate-holder" comprises at least three such meshing recess/protrusion pairs, and - wherein, for the recess/protrusion pairs, the lengths are selected in such a way that at room temperature, the recesses reach radially into the protrusions, in each case at most up to a radial spacing d, whose order of magnitude corresponds to that of the gap width S, and - and wherein for the recess/protrusion pairs, the width profiles are matched to each other, in the tangential direction, in such a way the recess can act as a guide rail, whose clearance sp in the tangential direction is less than S, for the corresponding protrusion and it is thus achieved that, both at room temperature and at higher temperatures, at which the plate expands more than the holder, the expanding plate is always anchored centrally in the holder, apart from, at most, the clearance sp, wherein the width profile in the guide regions of at least one of the protrusions, preferably of several protrusions, and particularly preferably of all protrusions, in the axial direction, i) has no edges, whereby jamming in the guide rail provided by the corresponding recess is made impossible, or ii) has parallel, straight walls at least in the radial subsection in which the recess is guided. - at room temperature, the circumference of the opening of the holder is greater than the circumference of the surface of the plate, whereby, when the plate is positioned centrally in the opening of the holder, a gap with a defined gap width S between the plate edge and the inner holder edge is provided, and - α2<α1, and - the plate edge has one or more protrusions, which, viewed from the center point of the circular surface, extend over protrusion lengths in a radial direction starting from the surface of the plate edge and reach into corresponding recesses with recess lengths of the holder edge, and/or the plate edge has one or more recesses, which, viewed from the plate edge, extend over recess lengths toward the center point of the circular surface, and corresponding protrusions of the holder edge with protrusion lengths reach into them, - wherein the system "plate-holder" comprises at least three such meshing recess/protrusion pairs, and - wherein, for the recess/protrusion pairs, the lengths are selected in such a way that at room temperature, the recesses reach radially into the protrusions, in each case at most up to a radial spacing d, whose order of magnitude corresponds to that of the gap width S, and - and wherein for the recess/protrusion pairs, the width profiles are matched to each other, in the tangential direction, in such a way the recess can act as a guide rail, whose clearance sp in the tangential direction is less than S, for the corresponding protrusion