In accordance with an example embodiment, an input text string is received. Then a k nearest neighbor (KNN) algorithm is used on the input text string to identify a set of leaf categories of an item listing schema that corresponds to the input text string. The set of leaf categories is reordered based on a statistical language model (SLM) algorithm performed on the input text string and an SLM for each leaf category in the set of leaf categories from the KNN recommendation service. A gradient boosting machine (GBM) is then used to fuse the reordered set of leaf categories, a log prior probability for each of the leaf categories, and scores for the KNN algorithm for each of the leaf categories to calculate an ordered list of recommended leaf categories with corresponding scores.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A system comprising: a k nearest neighbor (KNN) recommendation service executable by one or more processors and configured to perform a KNN algorithm on an input text string to identify a set of leaf categories of an item listing schema that corresponds to the input text string; a statistical language model (SLM) re-ranking module configured to reorder the set of leaf categories from the KNN recommendation service based on an SLM algorithm performed on the input text string and an SLM for each leaf category in the set of leaf categories from the KNN recommendation service; and a gradient boosting machine (GBM) configured to fuse the reordered set of leaf categories, a log prior probability for each of the leaf categories, and scores for the KNN algorithm for each of the leaf categories to calculate an ordered list of recommended leaf categories with corresponding scores. 2. The system of claim 1, wherein the KNN algorithm comprises a training phase and a classification stage, wherein the classification phase uses a user-defined constant k to classify an unlabeled leaf category by assigning a label that is most frequent among k training samples nearest to a point representing the unlabeled vector. 3. The system of claim 2, wherein nearness between training samples and a point is determined using Euclidean distance. 4. The system of claim 2, wherein nearness between training samples and a point is determined using an overlap metric. 5. The system of claim 1, wherein the SLM algorithm comprises determining a sentence log probability (SLP) for each leaf category. 6. The system of claim 1, wherein the SLM algorithm comprises calculating ranking scores for top leaf categories and calculating voting scores for the top leaf categories. 7. A method comprising: receiving an input text string; using a k nearest neighbor (KNN) algorithm on the input text string to identify a set of leaf categories of an item listing schema that corresponds to the input text string; reordering the set of leaf categories based on a statistical language model (SLM) algorithm performed on the input text string and an SLM for each leaf category in the set of leaf categories from the KNN recommendation service; and using a gradient boosting machine (GBM) to fuse the reordered set of leaf categories, a log prior probability for each of the leaf categories, and scores for the KNN algorithm for each of the leaf categories to calculate an ordered list of recommended leaf categories with corresponding scores. 8. The method of claim 7, wherein the KNN algorithm comprises a training phase and a classification stage, wherein the classification phase uses a user-defined constant k to classify an unlabeled leaf category by assigning a label that is most frequent among k training samples nearest to a point representing the unlabeled vector. 9. The method of claim 8, wherein nearness between training samples and a point is determined using Euclidean distance. 10. The method of claim 8, wherein nearness between training samples and a point is determined using an overlap metric. 11. The method of claim 7, wherein the SLM algorithm comprises determining a sentence log probability (SLP) for each leaf category. 12. The method of claim 7, wherein the SLM algorithm comprises calculating ranking scores for top leaf categories and calculating voting scores for the top leaf categories. 13. The method of claim 12, wherein the calculating voting scores comprises dividing one by the sum of one and the difference between a maximum SLM ranking score and an individual SLM ranking score for a leaf category. 14. A non-transitory machine-readable storage medium having instruction data to cause a machine to perform operations comprising: receiving an input text string; using a k nearest neighbor (KNN) algorithm on the input text string to identify a set of leaf categories of an item listing schema that corresponds to the input text string; reordering the set of leaf categories based on a statistical language model (SLM) algorithm performed on the input text string and an SLM for each leaf category in the set of leaf categories from the KNN recommendation service; and using a gradient boosting machine (GBM) to fuse the reordered set of leaf categories, a log prior probability for each of the leaf categories, and scores for the KNN algorithm for each of the leaf categories to calculate an ordered list of recommended leaf categories with corresponding scores. 15. The non-transitory machine-readable storage medium of claim 14, wherein the KNN algorithm comprises a training phase and a classification stage, wherein the classification phase uses a user-defined constant k to classify an unlabeled leaf category by assigning a label that is most frequent among k training samples nearest to a point representing the unlabeled vector. 16. The non-transitory machine-readable storage medium of claim 15, wherein nearness between training samples and a point is determined using Euclidean distance. 17. The non-transitory machine-readable storage medium of claim 15, wherein nearness between training samples and a point is determined using an overlap metric. 18. The non-transitory machine-readable storage medium of claim 14, wherein the SLM algorithm comprises determining a sentence log probability (SLP) for each leaf category. 19. The non-transitory machine-readable storage medium of claim 14, wherein the SLM algorithm comprises calculating ranking scores for top leaf categories and calculating voting scores for the top leaf categories. 20. The non-transitory machine-readable storage medium of claim 19, wherein the calculating voting scores comprises dividing one by the sum of one and the difference between a maximum SLM ranking score and an individual SLM ranking score for a leaf category.