Apple took an aggressive step against its biggest competitor over the past week, asking a California court to block sales of Samsung's Galaxy Nexus smartphone in the US. The filing isn't fully available yet, but news of the action came via a separate motion in which Apple accused Samsung of violating four Apple patents in the design of the Galaxy Nexus.

"[The Galaxy Nexus will] exacerbate the wide-ranging network effects that, in turn, enhance the appeal of that platform to the detriment of Apple iOS," a curiously vulnerable-sounding Apple filing reads. "It is a virtual certainty that there will be lost sales of other Apple products closely related to the iPhone attributable to the Galaxy Nexus purchases."

The Samsung Galaxy Nexus is the first Android-based handset to run Google's Android 4.0 system, which goes by the codename "Ice Cream Sandwich." Apple notes in the filing that the Galaxy Nexus has been described as "the most credible competitor to the iPhone so far" and admits that the device poses a "credible threat" to the iPhone.

However, unlike other Samsung handset and tablet devices that Apple has legally attacked in various countries, the Galaxy Nexus has a unique design that in no way mimics the look and feel of Apple's iPhone. So this is the first time that Apple has attacked Samsung for technical violations rather than for simply copying the design of its products.

The four alleged patent violations include technologies related to "slide to unlock," searching multiple sources simultaneously, misspelling alternatives, and, interestingly, one tied to creating links from useful information like phone numbers and addresses in a contact card. Apple previously won an International Trade Commission (ITC) injunction against HTC handsets that violated that last patent.

Unlike other companies in the mobile industry, Apple has tried to sue competitors that use designs and now technologies that Apple says it owns. Microsoft, by contrast, has created a terrifically successful mobile technology patent licensing program instead and has lined up most Android handset and devices makers. So Microsoft makes money virtually every time an Android device is sold.

And Samsung is a bigger foe than HTC. The company currently sells far more smartphones than does even Apple, and Samsung was the number-one seller of smartphones in all of 2011. And Apple lost a similar injunction request last April, with the court arguing that Apple didn't prove it would suffer irreparable harm if sales of a rival product weren't blocked.