When do we use dash instead of equality sign?

Question

I began reading "A Concise Introduction to Mathematical Logic" by Wolfgang Rautenberg and on the 17th page came up with the following notation: enter image description here

The author (as I can understand) uses dash sign instead of equality sign but I've never met such notation. Is it specific to Germany, to mathematical logic texts, or something else?

The problem was with the PDF viewer and I was stupid enough not to open document in another one. — Igor, Jan 06 '14 at 17:37
The main thing is that now i can read a book without questioning the notation. — Igor, Jan 06 '14 at 17:42
Mathematics does not make mistakes ! it is only in "applied" mathematics (like coding software), being performed by human (and limited) being, that you can find errors ... Of course, I'm joking. — Mauro ALLEGRANZA, Feb 13 '14 at 12:13

score 3 · Accepted Answer · answered Jan 06 '14 at 17:30

3

It appears as $=$ to me (and is on xix). Check the PDF viewer you are using.

answered Jan 06 '14 at 17:30

You're right. It was my viewer joking with me. – Igor Jan 06 '14 at 17:36

When do we use dash instead of equality sign?

1 Answers1