Mark  What you did 
5  Reason, apply, problem solve, present:
Correctly applies ideas to reach a clear, concise, correct, cleanly presented solution. Can reason
about ideas presented. Can apply them to different settings. etc. Minor technical flaws allowed.
Your explanations/documentation is clear and simple, gets to the point, presents the right few
concepts necessary to understand the solution.

4  As in 5 but lacks some clarity, not as concise as possible, some minor flaw, not a clean presentation.
Documentation/explanation is not focused, does not address key points
in any special way.

3 
Semantics: Demonstrates correct understanding of basic definitions, ability to correctly apply basic techniques,
theorem statements etc. Some major conceptual misunderstanding. Indicators are that fixing the problem would require a long discussion.

2  Some major flaw in the understanding of basic definitions, techniques, theorem statements.
Examples are: Applies theorems to wrong settings.
Does not understand the goal (ie tries to prove the wrong result).
Solves the wrong problem.

1  Syntax: Ability to restate given definitions, theorems, techniques. 