How are double stops / divisi indicated in violin scores?

One piece includes a square bracket , "[" in front of the phrase to indicate double stops. Another piece assumes no marks means "double stop," and specifically writes "divisi" where desired.

1. How do you notate a double stop?
2. What is the difference between Divisi and double stops?
3. How do you notate a violin tremolo?

How do you notate a double stop?

In performing a double stop, two separate strings are bowed or plucked simultaneously. Although the term itself suggests these strings are to be fingered (stopped), in practice one or both strings may be open. A triple stop is the same technique applied to three strings; a quadruple stop applies to four strings.

What is the difference between Divisi and double stops?

Divisi is used as a means of thinning out the chord texture. Double stops are effective when the music requires a strong accent. However, double stops add a rhythmic delay or bump of sorts, since they can never be played precisely simultaneously on string instruments.

How do you notate a violin tremolo?

Two notes are played as a tremolo on the same string as follows: the finger in the lower position fingers the string and keeps it pressed down while the other finger quickly and repeatedly stops and releases a higher note.