If Amazon concedes that states and localities have enforcement powers beyond their borders for taxing purposes, will Amazon also need to be subject to ALL of the sales regulations imposed by their customers' jurisdictions? Will I get a big pop-up saying that a switchknife of the length I've chosen isn't legal in my city? Will they have to check ID for M-rated games?

You're right, strictly speaking, but what I was referring to was commutivity of the algorithm, not necessarily the result. You want to know that whatever decides (a gt b) is also going to decide whether (b gt a).

Yes. At least for me with Cpp, using + for string concatenation leads to more headaches than it's worth. I prefer to use boost::format.

Operators imply commutivity (a+b = b+a). You can't guarantee that if the function is implemented by a or b. It's a bad idea that leads to subtle errors down the road.

Non-profits can and often do take in revenue in excess of their costs (they wouldn't be very stable otherwise!) The difference is what tax law allows them to do with those profits (reinvest in their business vs. distribute to the owners).

The value of goods and services is in the eye of the beholder. Parties engage in trade (and employment) because the perception is that both sides stand to gain.

It's all a wash as long as total revenue as a percentage of GDP remains the same, right? You're just collecting it from somewhere else (incentivizing/disincentivizing different things).

That said, all the taxes you've listed are probably better for society than sales tax. Disincentivizing consumption and targeting the poor are two things that generally aren't great for an economy.

But what about in a corporate environment, where the OWNER is distinct from the person in physical possession of the device? Can we at least have some basic infrastructure to ensure that when a device is going to be permitted to access sensitive resources/material, it has some verifiability of its state?

The inner sandbox uses static analysis to detect security defects in untrusted x86 code. Previously, such analysis has been challenging for arbitrary x86 code due to such practices as self-modifying code and overlapping instruc- tions. In Native Client we disallow such practices through a set of alignment and structural rules that, when observed, insure that the native code module can be disassembled reliably, such that all reachable instructions are identified during disassembly. With reliable disassembly as a tool, our validator can then insure that the executable includes only the subset of legal instructions, disallowing unsafe machine instructions. The inner sandbox further uses x86 segmented memory to constrain both data and instruction memory references. Leveraging existing hardware to implement these range checks greatly simplifies the runtime checks required to con- strain memory references, in turn reducing the performance impact of safety mechanisms.

As long as you weren't trying to write self-modifying code (and note most compilers won't do this), your performance impacts are basically restricted to checking non-local jumps. Not strictly native, but close enough.

That's provably untrue. See AppArmor and SE-Linux, both of which operate without creating a virtual machine (only implementing replacement system calls).

Differential Geometry will give you the mathematical foundation for expressing non-flat spaces. From there, GR is "just" the Einstein Field Equations and the implications thereof. And compared to, say, quantum mechanics, there's very few solvable exact solutions to make case studies out of (black holes and possible evolutions of the universe, really).

Springer has an OK book on Differential Geometry, and then you want to move on to Gravitation, by Misner, Thorne, and Wheeler.