rlm@2: #+TITLE: Notes for SICM
rlm@2: 
rlm@2: * Complex numbers
rlm@2: 
rlm@2: 
rlm@2: * Multidimensional Structures
rlm@2: ** Tuples
rlm@2: - Tuples are a new data type: sequences with /spin/. A tuple can be either spin-up or spin-down.
rlm@2: - A pair of compatible tuples can be *contracted* into a single number.
rlm@2:   - Tuples are compatible if they have the same length and opposite
rlm@2:     spin, and if their corresponding pairs of items are either both
rlm@2:     numbers or both compatible tuples.
rlm@2:   - To contract tuples, take the sum of the products of corresponding
rlm@2:     pairs of items. (To take the product of compatible tuples,
rlm@2:     contract them.)
rlm@2: 
rlm@2: *Generic Arithmetic:* To multiply two tuples, check to see if they are
rlm@2:  compatible. If they are, contract them. If they aren't, multiply each
rlm@2:  item of the second tuple by the first tuple.
rlm@2: 
rlm@2: To multiply a tuple by a number, multiply each element of the tuple by
rlm@2: the number.
rlm@2: 
rlm@2: ** Matrices
rlm@2: Uses incanter matrices.