> For the complete documentation index, see [llms.txt](https://peridot-finance.gitbook.io/peridot-protocol/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://peridot-finance.gitbook.io/peridot-protocol/technical-architecture/evm/dual-investment/erc1155dualposition.md).

# ERC1155DualPosition

ERC‑1155 token representing Dual Investment positions. Transfers are disabled (mint/burn only) to keep positions atomic until settlement.

## Position Encoding

* tokenId = `keccak256(underlying, strike, expiry, direction, marketId[, user])`.
* Use `generateTokenIdForUser(...)` to avoid multi‑user collisions.

## Data Model

```
struct Position {
  address user;
  address cTokenIn;  // base asset (input)
  address cTokenOut; // quote asset (settlement)
  uint128 notional;
  uint64  expiry;
  uint64  strike;   // 18‑decimals
  uint8   direction; // 0=CALL, 1=PUT
  bool    settled;
}
```

## Key Functions

* `mintPosition(to, tokenId, amount, Position)` \[onlyAuthorized]
  * Stores `Position`, mints ERC‑1155 amount; requires future `expiry`.
* `burnPosition(from, tokenId, amount)` \[onlyAuthorized]
  * Burns; flags as `settled` if balance reaches zero.
* `setAuthorizedMinter(minter, authorized)` \[onlyOwner]
* Views: `getPosition(tokenId)`, `isExpired(tokenId)`, `isSettled(tokenId)`.

## Transfers

* `_update` overridden to require `from==0 || to==0` → only mint or burn allowed.