# 2020-08-03

Worked through Axler exercises in section 3.F, 1-27

1

Scalar multiplication "expands" (ejude) along a "spatial" (entation) dimension.

3

When looking for a linear map out of a finite dimensional space, psuedo-visually pair basis vector with desired result

5

Mental sense of "type matching" (direna)

Mental proof of map linearity: A shifting/sliding "transition" between equivalent formulas

Vertical stacking for tuple addition, merge downwards

7

Was going to use the "define a map by how it acts on a basis" trick, felt a sense of not being confident in how that works. Felt "pressing blankness" in stomach (below xyphoid process, above navel) (patrodola).

Proving additivity mentally: Given two linear combinations of the same terms, one with constants ai and the other with bi, if adding them up yields a linear combination with (ai + bi), "slide" the bs down and over to the right entationally.

After re-proving the unique existence of a map based on how it acts on basis, felt a need to talk myself through the specifics as applied to the problem at hand… No more full on patrodola but still a vague "anxiety" to confirm understanding.

Seems like uncertainty stems from "non-constructive" assertion that the functional in question is in fact linear? Proving it helped the understanding.

8

To prove linear independence, often treat each vector as symbolic-entational and identify one "component" symbol (e.g. x2 or (1, 0)) that is only present in one vector, showing that its coefficient must be 0 if the linear combination is, and then dropping that vector and iterating

11

Felt uncertain about the definition of "rank"… Is it a lack of something? Fuzziness when mentally "pulling up" the page it's defined on?

12

Extended sequence of symbolically progressing/"shifting" terms one into another (valusing). Needed to work to "recall" definitions at points, work to hold "current" state active if possible. Reach end, sometimes satisfied and sometimes retrace?

Increase "the crow"/workspace! Save on paper?

19

When asserting a dual basis is a basis, possible patrodola (less pressing?)… Feeling seems associated with "lookup".

20

Verbalizing definitions/suppositions, a sort of entational "scan" over implications

22

Almost a commerelial "conversation" walking through the proof, possibly some monitoring for a sense of validity? (didn't make any errors so unsure)