token-id-bijective-mapping-reversible

IN premise — summaries/2026-08-24/wiki-Transformer_deep_learning_architecture-chunk-2.md

Created 2026-08-24T17:11:25+00:00

The token-to-integer-ID mapping in transformer tokenization is bijective (reversible), which is critical for the decoder to convert output integer IDs back into legible text without loss.

Summary

Every word fragment the model works with has a unique number, and every number maps back to exactly one word fragment, so there is no ambiguity in the round trip. This is what lets the system turn its raw numerical predictions back into readable sentences without losing or swapping words.