Balanced Incomplete Block Designs and construction for k=4
Move steiner_striple_system from block_design.py to bibd.py
Rebase on 5.13.beta2
Trac #15288 : Theorem 7.20 is now a function of its own, plus some fixes
trac #13917: IndependentSets class
trac #13917: add more documentation
trac #13917: doctests
trac #13917: A couple of mistakes
documentation improvement
Todo section
trac #13917: A misnamed function
remove the TODO and put the comment in NOTE
trac #13917: Broken doctest
remove deprecated
remove spurious cruft, presumably from preious commit, caused by eclipse
fix doctests
trac #16019: Broken Connected Components for immutable digraphs
trac #15288: Rebase on updated #15287
Trac #16024: fixed incorrect deleting of states in finite state machine
Improved Docstring for FiniteStateMachine.delete_state