intuitive – with PUT option, first look

When I read financial articles, I find PUT options harder to understand than most derivatives. Here’s my summary

–> You use a put insurance  when you think that underlying might fall.
–> A put insurance let’s you unload your worthless asset and cash in a reasonably high strike price

Here’s a longer version

–> You use a put insurance (on an underlying) at price $100 when you think that underlying might fall below $100. This insurance lets you “unload” your asset and cash in $100. Note most put or calls traded are OTM.

A good thing about this simplified intuitive definition is, current underlying price doesn’t matter.Specifically, it doesn’t matter whether current underlying price is below or above strike (ie in the money or out).

Q: both a short position (in the underlying) and a put holder benefits from the fall. Any difference?
A: I feel if listed puts are available, then they are preferable to holding a short position. Probably cheaper and don’t tie up lots of cash.

Q: how about the put writer?
A: (perhaps not part of the “intuitive” first lesson on puts)
A: sound byte — an “insurer” .
A: therefore they don’t want volatility.  They want underlying price to stay high or at least be stable

Simplest underlying is a stock.

exceed copy-paste between win32 and X-windows

Using exceed, it can be a challenge to set up copy-paste between win32
and X windows. I know 2 options.

Note I always enable auto-copy-x-selection and
auto-paste-to-x-selection.

— option: X-selection-page -> X Selection Associated With Edit
Operations set to Primary —
Lesson? “Primary” is the default. In this mode, don't use the xwin
context-menu.

* Simple-Select (without middle-button or context menu) to copy from
unix, paste to win32? Yes
* Simple-Select (without middle-button or context menu) to copy from
unix, middle-button to paste to unix? yes
* Select from win32, middle-button to paste in unix? Yes
* Select from win32, context-menu->edit->paste in unix? no

— option: X-selection-page -> X Selection Associated With Edit
Operations set to Clipboard —
This is suggested on some webpage. It also enables copy-paste between
unix and windows.

generic subtyping – arrays vs collections

based on [[java generics and collections]]

1)
List<Integer> ints = Arrays.asList(1,2,3);
List<Number> nums = ints; // uncompilable
nums.add(0.001); // mistake caught by compiler
// list of integer is NOT a subtype of list of numbers, but below, array-of-integer is indeed a subtype of array-of-numbers!
2)
Integer[] intArray = {1,2,3};
Number[] numArray = intArray; // compilable
numArray[0] = 0.001; // run time error; compiler negligence
3)
ArrayList is indeed a subtype of List

which banks ask differentiating questions

(another blog post)

If an interview question is too tough, then strong or fake candidates both fail. If question is too common, then both pass. Good differentiating questions let the strong candidates shine through. Differentiating candidates depends on

* non-standard (but not obscure) questions, or
* drill-in on standard questions, or
* an interviewer capable of seeing the subtle differences among answers to standard questions.

If you have “none of the above”, then you can't differentiate candidates.

Most interview questions are open-ended. I (not yet a strong candidate) can give super long answers to sleep-vs-wait, interface-vs-abstract-class, arrayList-vs-linkedList, “how to prevent deadlock”…. However, many interview questions are so common that candidates can find perfect standard answers online. A strong interviewer must drill in on such a stock question to test the depth of understanding.

GS, google, lab49, MS, barc cap have good interviewers.