Arithmetic / Range Coding Checkpoint

1. Arithmetic coding represents a message as:

A sub-interval of [0,1) A Huffman tree A fixed-length bitstring A permutation

2. Underflow handling is needed when:

The interval straddles the midpoint The input is empty The symbol is EOF The probabilities are uniform

3. A static model requires:

Encoder and decoder share the same frequencies No EOF symbol Random padding A prefix tree

4. Arithmetic coding can achieve:

Fractional bits per symbol on average Only integer bits per symbol Zero-length codes for any symbol Compression without a model

5. If probabilities are mismatched, expected length equals:

Cross-entropy Zero The alphabet size The tree height