# OpenOffice Tutorial: Enter the "double arrow left and right" symbol (if and only if) between variables

How-To: OpenOffice Tutorial: Enter the "double arrow left and right" symbol (if and only if) between variables

- To enter the "double arrow left and right" symbol between variables, first click on the "math commands window" here.
- Once the cursor appears, type in the first variable. In this case, it is the letter "a."
- Next, press space and type in "dlrarrow" This should display the "double arrow left and right" or the material equivalence symbol.
- Afterwards, press space and type in the next variable. In this example, it is the letter "b."
- Great! We have entered the "double arrow left and right" symbol between two variables. Congratulations!

*by Kaj Kandler*

# Enter the "double arrow left and right" symbol (if and only if) between variables

This screencast demonstrates how to enter the "double arrow left and right" symbol (if and only if) between variables. You learn:

- How to look for the Commands Window.
- How to enter the "double arrow left and right" symbol or material equivalence.
- How to set the relation "a if and only if b."

# Advanced topics

For advanced functionality with similar results see:

- Enter the "double arrow left" symbol between variables (Material Implication)
- Enter the "double arrow right" symbol between variables(Material Implication)
- Set the relation "a is congruent to b"
- Set the relation "a divides b"
- Set the relation "a does not divide b"

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