1. A method for providing a reference model having an acceptance range on a portable data carrier for biometrically recognizing a user of the data carrier, wherein a biometric comparison vector which lies within the acceptance range of the reference model is accepted as coming from the user, comprising the steps of: defining, by a processor of the portable data carrier, the reference model by model nodes which are formed from biometric reference vectors in each case coming from the user, during an initial training phase, wherein for generating the reference model a multitude of biometric reference vectors is recorded, and wherein the reference model is defined piecewise by local models each having a validity range, and adding a model node to the reference model, during an application phase of the reference model upon checking, by the processor of the portable data carrier, a comparison vector when the comparison vector lies outside the acceptance range of the reference model and it is certain that the comparison vector actually comes from the user, wherein a local model is formed by at least one model node, and that for recognizing the user that local model of the reference model is used in whose validity range a biometric comparison vector of the user lies, wherein each local model is assigned in each case a validity range which is determined by a probability distribution which is assigned to the at least one model node forming the local model, wherein the width of the probability distribution of the model node results from the probability distributions of neighboring model nodes, and that the probability distribution assigned to a model node indicates a recognition quality of a biometric comparison vector accepted as coming from the user which lies within the validity range of that local model which is formed by at least the model node.