# Thread: What does chevron mean in set theory?

1. ## What does chevron mean in set theory?

I am trying to pick through Karp's paper on computational complexity "reducibility among combinatorial problems". In it he defines a deterministic algorithm. I cannot understand the line:
a finite aphabet [delta symbol] such that [delta symbol]* [chevron symbol] R = [null set symbol]
Where I put chevron symbol is an inverted v (like logical and). What does this mean. An intersection symbol is shown later on so I assume that intersection symbol was available and would have been used if that was appropriate here.

Of course one cannot google on a symbol whose name one does not know.

Bob.

2. Does it say what R is?

3. The rest of it is:
A countable set D (the domain)
A countable set R (the range)
a finite alphabet......... [as before]
an encoding function e: d->[delta symbol]*
a transition function [t like symbol]: [delta symbol]* -> [delta symbol]*[union symbol] R

He is defining a model for all deterministic algorithms

hth

4. Got it, I think he means intersection and the chevron is a typo for intersection symbol.
In the wider computer science context, my GUESS is that D is the problem domain, e is a "reasonable" (non-unary) encoding, R is the set of states, delta is the alphabet (finite set of symbols used to encode a problem d from D) and he is trying to say that the set of states and the set of alphabet symbols do not intersect.