add higher arithmetic formulations

Squashed commit of the following:

commit 433749e614db22b5550292891fc10a20fd2b19b3
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Tue Oct 29 07:47:52 2013 +0100

    superb

commit cec75455464e43783207122ac8133597f50724a3
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Tue Oct 29 07:36:16 2013 +0100

    looks very good now

commit 8dca90994a04ac31bbca887571c614c8d2ea9397
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Tue Oct 29 07:31:41 2013 +0100

    add new test

commit 0643f71c30cd1f97fb65baeae6f03add73eaab5b
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Tue Oct 29 07:26:36 2013 +0100

    now it works :D

commit cf89e01295c9bd19466b642496daec990d0904a1
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Tue Oct 29 07:17:05 2013 +0100

    tests are failing

commit dc16e54825bb7c0f52bdf2aaf3f2a4996e6ca345
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Tue Oct 29 06:53:57 2013 +0100

    compile errors fixed

commit 9a307fb72b46bebee04bc86627427ea4c2151268
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Tue Oct 29 06:49:40 2013 +0100

    commented it out

commit 5f79396c925e42b11b1bfe07185eb98bf3ae1f54
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Tue Oct 29 06:49:12 2013 +0100

    must be tailrecursive otherwise its to expensive

commit 4661647e9eb3f03e16c6a6322011b4d22e8318e8
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Tue Oct 29 06:47:37 2013 +0100

    should work, but i'm not shure

commit 99a089a2950dd97adce38caa8d73a0057a53da84
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Tue Oct 29 06:06:39 2013 +0100

    step by step

commit 3b1e5d6bb2ddaf5da797a8085154e5862290ae6e
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Tue Oct 29 05:37:23 2013 +0100

    add some predicates

commit 6d7be7a9d8964e71f60b3fd5b6fe77d46b87e445
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Tue Oct 29 05:26:46 2013 +0100

    reformat

commit c2fae94fe8133641becc3273f37c8c7fbd2373d2
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Tue Oct 29 05:04:49 2013 +0100

    moved is function to Predicate and created some tests

commit 56adcd69e532015c760e1c652f1f801e249733b6
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Mon Oct 28 13:12:54 2013 +0100

    ok it compiles lets see what happens when i'm writing tests :D

commit bc2144041c16612f64ffa70affef4a3cef4f9119
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Mon Oct 28 13:09:47 2013 +0100

    superb test must be adjusted but thats ok

commit 20f640072b5162c6c258bd533ad6f364b4f5c06e
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Mon Oct 28 12:56:59 2013 +0100

    now it can't compile because i defined something stupid

commit 948980c970dcbf9525d73638f14d77edac3f0dcf
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Mon Oct 28 12:42:56 2013 +0100

    step by step

commit 9f1a5d0a4ac06def2125f744bb1b8f101ab33c53
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Mon Oct 28 12:41:04 2013 +0100

    step by step

commit def9ec47d869c7927eb1d69bc88c90f95d30fa34
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Mon Oct 28 12:35:47 2013 +0100

    docu

commit c8b276cb8dea0e7ca05d2d1a7c64ce87ff5cecbd
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Mon Oct 28 12:33:35 2013 +0100

    sugar

commit 381370a65096219d053321e1778fe5ec37a4c889
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Mon Oct 28 12:21:00 2013 +0100

    commentary and format

commit 8909d3561947ca661c4ec9673679502962b63d14
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Mon Oct 28 12:19:42 2013 +0100

    keep less and bigger files

commit 6b4e915f96cb2956d56f4881718540827071d3b4
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Mon Oct 28 12:16:16 2013 +0100

    don't know just commited

commit bb947fbada30a52d3d8439404728162a355ab040
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Mon Oct 28 12:13:35 2013 +0100

    getters for the elements

commit 5474b86555f904163e7070efec75055a286380b0
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Mon Oct 28 12:06:46 2013 +0100

    glued almost everything in the arithmetic element

commit a84933ab61e15a6178978ffaf4ab70add5b7fce7
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Mon Oct 28 11:54:24 2013 +0100

    test variables and tought about the way the arithmethic should work.

commit a22c6eb5bc8718b9dcb995a4a8e19c77a291c65d
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Mon Oct 28 11:44:13 2013 +0100

    definied month and stuff

commit a3c11ace4cadfef7724c03e58d378d6838ed7570
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Mon Oct 28 11:17:18 2013 +0100

    add implicite

commit 0287461454244ad915cd293c9953892488c33121
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Mon Oct 28 11:15:35 2013 +0100

    starting with arithmetic elements

commit 78b0ac7da6bb61b4e8ca1f49be16526feef1d6ff
Author: Ingolf Wagner <palipalo9@googlemail.com>
Date:   Sun Oct 27 12:33:43 2013 +0100

    moved default converter