Dependencies among operations are illustrated with precedence relationships, which indicate the order in which the operations need to be performed.

**COMMON PRECEDENCE TYPES**

The most common types of dependencies are the following four (4):

1. Finish-To-Start (FS): Activity B **can**** **begin after A is finished.

In other words: Finish A ≤ Start B

2. Start-To-Start (SS): Activity B **can** start at the same time as A.

In other words: Start A ≤ Start B

3. Finish-To-Finish (FF): Activity B can finish at the same time as A.

In other words: Finish A ≤ Finish B

4. Start-To-Finish (SF): Activity B **can** finish at the same time as A starts.

In other words: Start A ≤ Finish B

**ALICE'S CUSTOM PRECEDENCE TYPES**

In ALICE, the above relationship types are extended by adding the "At" type, which imposes the type of dependency. Therefore, the additional precedency types are transformed to:

1. Finish - At - Start (**FaS**): Activity B **must** begin after A is finished.

Or: Finish A = Start B

2. Start - At - Start (**SaS**): Activity B **must** start at the same time as A.

Or: Start A = Start B

3. Finish - At - Finish (**FaF**): Activity B ** must **finish at the same time as A finishes.

Or: Finish A = Finish B

4. Start - At - Finish (**SaF**): Activity B ** must **finish at the same time as A starts.

Or: Start A = Finish B

Be mindful when using the custom precedence types, as they impose a very strict relationship between activities, which can render your schedule infeasible.

# Further Resources

- Recipes
- Recipes: How to Work with the Recipe Matrix
- Recipes: Temporary and Demolition Recipes
- Recipe Fundamentals
- Recipes: Importing of Recipe Matrix from Excel
- Recipes: Export Recipe Matrix