Advantage in being first to copyleft a new algorithm? Say I have created a new (DSP) algorithm. Will I have some advantage if I open source the algorithm under copyleft licence (GPL etc.)? From what I know about licensing this should lock people out from using the exactly same code as closed source, but would they be able to "rewrite" the algorithm as closed source? Note: I fear this may actually be two separate problems: open sourcing a known algorithm open sourcing a new algorithm I don't really know if the algorithm is new but it has not been released as open source yet. Since I am from the European Union do I need to look for software patents if I wanted to copyleft it?
Algorithms are not subject to copyright. A particular implementation can be copyrighted, but an algorithm itself can't be copyrighted. Someone re-implementing the algorithm with their own code has done nothing to give you copyright claims against their work, and is not bound by any software license you use. That's what patents are for.
In general, unless the license contains a clause which allows it to be modified at a later date through some defined means (publication, revocation of existing license etc) then you are free to continue to use the existing version of the software under the original license terms. So make sure you pin your versions! Look out for clauses such as exists in the GPL which allow the recipient of the distributed binary or code to choose what version of the GPL to apply if the original author does not state (GPLv2 Clause 9) as they then allow recipients to bind you, the distributor, to versions you might not agree with (eg the switch to GPLv3 with its patents clauses).
Ideas (methods of playing, game mechanics, strategy, goals) cannot be protected by copyright. But any part of a creative work can. So, no copying of drawings, patterns, images, sounds, or the element. I suppose copying the software code is not an issue here, but it can, obviously, also not be copied. And nothing in your game can look like someone's else trademark.
My opinion is that the copying of a single API endpoint, "run" that takes a function as an argument is not infringement. I can think of several lines of argument that get to this same conclusion: Originality: It doesn't exhibit the modicum of creativity required by the originality test. (Feist) Short phrases doctrine: It is a short word or phrase, which both the copyright office (Copyright Office Circular, 37 CFR 202.1) and courts (e.g. Hutchins v. Zoll) have declared ineligible for copyright. Merger: The merger doctrine allows reuse of an expression if it is one of only a very few number of ways of expressing an idea. I can't think of many other ways to express a function intended to run a function other than with the verb "run". Scènes à faire: It is not infringement to use an expression if it has become standard, stock, or common in a particular setting. Naming a function "run" is common in the programming community. Any one of these alone would be enough to rule out copyright infringement by taking this individual component of Excel's API. Note: Whether merger and scènes à faire are part of the originality/copyrightability analysis or part of the infringement analysis is not uniform across circuits. For example, the 6th circuit considers both merger and scènes à faire part of the copyrightability analysis. But, the 2nd and 9th circuits treat them as part of the infringement analysis and in the 9th circuit, they are affirmative defenses.
There are now 2 works. An original, abandoned work, and a new, derivative work. The original creator owns the copyright over the original, and the new person owns copyright over the derivative he created. In your scenario, it will be the new creator, who will have the right to sue, if the gpl of the new work has been infringed
The reason is 17 USC 106: the owner of copyright under this title has the exclusive rights to do and to authorize any of the following... (2) to prepare derivative works based upon the copyrighted work The original picture is the underlying protected work. The ASCII reproduction is a derivative work. If you get permission to make the derivative work, it is okay. Otherwise, it is copyright infringement. There is an escape clause, "fair use", which amounts to taking a chance that you won't be sued and then arguing that you didn't do them any prohibited harm. If you make any money off of the game, you have a major strike against you. I suggest reading the fair use FAQ; basically, it is really hard to know how a fair use defense will fare, but based on prior cases, I'd say it's infringement, not fair use.
Broadly speaking, the difference is the "sharealike" clause of CC-BY-SA. Any derivative of a CC-BY-SA work must itself be licensed CC-BY-SA, whereas a derivative of an "MIT with attribution" work can be under any license the author wants. There are a number of other differences in the fine print (eg. CC forbids DRM, where MIT doesn't), but that's the big one.
Software licenses are protected by copyright, meaning that you need the author's permission to copy them. One way to get permission is to buy a license, since many of them are for sale. Sometimes (e.g. CC licenses) a license to copy the license is granted. You can also read and understand what is in a license, and use that knowledge to write your own. This is different from copying the license, since what you are extracting from the existing licenses is the ideas, not the specific expression.