Module arithmetic 

Pure height-to-epoch arithmetic. Filled by the height_epoch_arithmetic domain (HEA-*).

arithmetic — pure height-to-epoch mapping functions

Introduced by: STR-002 — Module hierarchy (SPEC §13).

Owners: HEA-001 through HEA-004 (Phase 4).

Spec reference: SPEC.md §5

Functions

ensure_checkpoint_block_empty

Enforces the empty-checkpoint-block invariant.

epoch_checkpoint_height

Returns the checkpoint (last) L2 block height in the given epoch.

epoch_for_block_height

Maps an L2 block height to its epoch number.

first_height_in_epoch

Returns the first L2 block height in the given epoch.

is_checkpoint_class_block

Returns true if height is genesis or an epoch checkpoint block.

is_epoch_checkpoint_block

Returns true if height is an epoch checkpoint block (divisible by BLOCKS_PER_EPOCH).

is_first_block_after_epoch_checkpoint

Returns true if height is the first block after an epoch checkpoint.

is_genesis_checkpoint_block

Returns true if height is the genesis checkpoint block (height == GENESIS_HEIGHT).

l1_range_for_epoch

Returns the (start_l1_height, end_l1_height) for a given epoch.

last_committed_height_in_epoch

Returns the last L2 height included in this epoch’s checkpoint.