- || -- a binary operator, often used for vertical concatenation

`ChainComplexMap | ChainComplexMap`(missing documentation)- GradedModuleMap | GradedModuleMap -- a binary operator, often used for horizontal concatenation
- Array | Array, see List | List -- join lists, sequences or arrays
- List | List -- join lists, sequences or arrays
- Sequence | Sequence, see List | List -- join lists, sequences or arrays
- Matrix | Matrix -- join matrices horizontally
- Matrix | RingElement, see Matrix | Matrix -- join matrices horizontally
- Matrix | ZZ, see Matrix | Matrix -- join matrices horizontally
- RingElement | Matrix, see Matrix | Matrix -- join matrices horizontally
- RingElement | RingElement, see Matrix | Matrix -- join matrices horizontally
- ZZ | Matrix, see Matrix | Matrix -- join matrices horizontally
- Net | Net -- join strings or nets
- String | String, see Net | Net -- join strings or nets
- String | ZZ, see Net | Net -- join strings or nets
- ZZ | String, see Net | Net -- join strings or nets
- ZZ | ZZ -- logical or

This operator may be used as a binary operator in an expression like `x|y`. The user may install binary methods for handling such expressions with code such as

X | Y := (x,y) -> ...

where `X` is the class of `x` and `Y` is the class of `y`.